Richard Forbes

Dr Richard Forbes


Visiting Reader (formerly Reader) in High Electric Field Nanoscience
MA, PhD, DSc, EurIng, CEng, CPhys, FIET, FInstP, SMIEEE
+44 (0)1483 689140
AB 04
After 11 am, most days.

My publications

Publications

Forbes RG (2004) On the use of energy-space diagrams in free-electron models of field electron emission, SURFACE AND INTERFACE ANALYSIS 36 (5-6) pp. 395-401 JOHN WILEY & SONS LTD
An improved method is reported for deriving the equations for cold field electron emission from a free-electron metal. It is shown that the derivation of these equations can be presented as a straightforward double integral in a space where the vertical axis represents the total electron energy, and the horizontal axis represents the component of electron kinetic energy parallel to the emitter surface. A general approach is developed that applies to a tunnelling barrier of any shape. It is shown that the temperature-correction factor derived by Murphy and Good for emission through an image-rounded barrier also applies to a more general barrier. For the standard image-rounded barrier the results coincide with those of Murphy and Good, but the derivation is more straightforward mathematically and the physics involved can be visualized more easily. The method developed here should be a good foundation for developing an improved theory of cold field electron emission from semiconductors: the main object of the paper is to lay this foundation. Copyright (C) 2004 John Wiley Sons, Ltd.
Forbes RG (2003) Field electron and ion emission from charged surfaces: a strategic historical review of theoretical concepts, ULTRAMICROSCOPY 95 (1-4) PII S0304-3991(02)00293-0 pp. 1-18 ELSEVIER SCIENCE BV
Suvorov VG, Forbes RG (2004) Theory of minimum emission current for a non-turbulent liquid-metal ion source, MICROELECTRONIC ENGINEERING 73-4 pp. 126-131 ELSEVIER SCIENCE BV
FORBES RG (1979) DISCRETE-CHARGE MODEL OF A FIELD-ION EMITTER SURFACE, ULTRAMICROSCOPY 4 (3) pp. 390-391 ELSEVIER SCIENCE BV
FORBES RG (1982) TOWARDS A CRITERION FOR THE A-PRIORI PREDICTION OF FIELD-EVAPORATION MECHANISM, JOURNAL OF PHYSICS D-APPLIED PHYSICS 15 (8) pp. L99-L104 IOP PUBLISHING LTD
Zurlev DN, Deane JHB, Forbes RG (2006) Forbidden ions in field evaporation, IVNC and IFES 2006 - Technical Digest - l9th International Vacuum Nanoelectronics Conference and 50th International Field Emission Symposium pp. 87-88
Forbes RG, Deane JHB (2006) Analytical approximations for the special elliptic functions of standard Fowler-Nordheim theory, IVNC and IFES 2006 - Technical Digest - l9th International Vacuum Nanoelectronics Conference and 50th International Field Emission Symposium
Forbes RG (2010) P2-32: Accurate calculation of the Schottky-Nordheim barrier functions, Proceedings of 23rd International Vacuum Nanoelectronics Conference pp. 183-184
This poster records the various methods historically used to accurately calculate the Schottky-Nordheim barrier functions used in tunnelling theory. This can now be done via a spreadsheet. Electronic copies of a suitable spreadsheet can be made available. This extended abstract also contains some underlying basic theory.
FORBES RG (1981) THE INFLUENCE OF HYPERPOLARIZABILITY AND FIELD-GRADIENT POLARIZABILITY ON FIELD ADSORPTION BINDING-ENERGIES FOR HE ON W(111), SURFACE SCIENCE 108 (2) pp. 311-328 ELSEVIER SCIENCE BV
FORBES RG, LJEPOJEVIC NN (1991) CALCULATION OF THE SHAPE OF THE LIQUID CONE IN A LIQUID-METAL ION-SOURCE, SURFACE SCIENCE 246 (1-3) pp. 113-117 ELSEVIER SCIENCE BV
Forbes RG (2012) Field enhancement factor for a tall closely-spaced array of identical conducting posts, and implications for fowler-nordheim theory, Technical Digest - 25th International Vacuum Nanoelectronics Conference, IVNC 2012 pp. 284-285
This paper derives an approximate formula for the field enhancement factor for a tall closely-packed array of identical conducting posts. It confirms a formula derived from the work of Zhbanov et al. [J. Appl. Phys. 110, 114311 (2011)], but displays the principles underlying collective screening more clearly. A formula for the area efficiency of emission (±
) for this array is also derived. Since ±
j1, it follows that a macroscopic pre-exponential correction factor (»
) must be included in the formula for the macroscopic ("LAFE-average") emission current density (J
) for a large-area field emitter (LAFE). Omission of »
may cause great theoretical over-prediction of the value of J
. © 2012 IEEE.
FORBES RG (1985) SEEING ATOMS - THE ORIGINS OF LOCAL CONTRAST IN FIELD-ION IMAGES, JOURNAL OF PHYSICS D-APPLIED PHYSICS 18 (6) pp. 973-1018 IOP PUBLISHING LTD
Forbes RG (1978) Reply to comments on "Opinion on SI", Physics Bulletin 29
FORBES RG, MUNOZ RA (1980) A PRELIMINARY EXPLORATION OF ION-DIPOLE CORRELATION ENERGIES, ULTRAMICROSCOPY 5 (2) pp. 265-265 ELSEVIER SCIENCE BV
Fischer A, Mousa MS, Al-Rabadi AN, Forbes RG (2010) P1-26: Influence of tip curvature on field electron emission characteristics, Proccedings of 23rd International Vacuum Nanoelectronics Conference, IVNC 2010 pp. 78-78
This poster explores the influence of tip curvature on field electron emission characteristics. We look at predicted changes in: Fowler-Nordheim plots (which tend to become curved); the dependence of notional emission area on voltage; and the slope and intercept correction functions.
FORBES RG, CHIBANE K, ERNST N (1984) DERIVATION OF BONDING DISTANCE AND VIBRATION FREQUENCY FROM FIELD EVAPORATION EXPERIMENTS, SURFACE SCIENCE 141 (1) pp. 319-340 ELSEVIER SCIENCE BV
Forbes RG (2006) Another look at the classical calculation of evaporation fields, IVNC and IFES 2006 - Technical Digest - l9th International Vacuum Nanoelectronics Conference and 50th International Field Emission Symposium pp. 85-86
Forbes RG (1996) The liquid metal ion source as an electrically driven vena contracta, and some comments on LMIS stability, JOURNAL DE PHYSIQUE IV 6 (C5) pp. 43-47 EDITIONS PHYSIQUE
Zurlev DN, Forbes RG (2003) Field ion emission: the effect of electrostatic field energy on the prediction of evaporation field and charge state, JOURNAL OF PHYSICS D-APPLIED PHYSICS 36 (17) PII S0022-3727(03)63916-1 pp. L74-L78 IOP PUBLISHING LTD
CHONG JWW, FORBES RG (1992) DESIGN OF BASIC CMOS CELL LIBRARY, IEE PROCEEDINGS-G CIRCUITS DEVICES AND SYSTEMS 139 (2) pp. 256-260 IEE-INST ELEC ENG
Forbes RG (1978) More confusion over the Avogadro constant, Physics Education 13 (1) pp. 5-6
Forbes RG (1976) A GENERALIZED THEORY OF STANDARD FIELD-ION APPEARANCE ENERGIES, SURF SCI 61 (1) pp. 221-240 ELSEVIER SCIENCE BV
Duffell J, Forbes RG (1978) FIELD-ION IMAGE-CONTRAST - THE GAS-DISTRIBUTION HYPOTHESIS REEXAMINED, J PHYS D APPL PHYS 11 (9) pp. L123-L125 IOP PUBLISHING LTD
Xanthakis JP, Forbes RG (2005) Field screening by amorphous carbon thin films, Technical Digest of the 18th International Vacuum Nanoelectronics Conference, IVNC 2005 2005 pp. 107-108
Qin X-Z, Wang W-L, Xu N-S, Li Z-B, Forbes RG (2011) Analytical treatment of cold field electron emission from a nanowall emitter, including quantum confinement effects, PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES 467 (2128) pp. 1029-1051 ROYAL SOC
FORBES RG (1981) CHARGE HOPPING AND CHARGE DRAINING - 2 MECHANISMS OF FIELD DESORPTION, SURFACE SCIENCE 102 (1) pp. 255-263 ELSEVIER SCIENCE BV
Fischer A, Mousa MS, Fischer A, Deane JHB, Forbes RG (2012) Illustrating field emission theory by using plots of transmission probability and barrier strength, Technical Digest - 25th International Vacuum Nanoelectronics Conference, IVNC 2012 pp. 290-291
This poster is part of a continuing attempt to make field emission theory more transparent. When interpreting current-voltage characteristics related to cold field electron emission (CFE), it is widely assumed that these are controlled and dominated by the behaviour of the tunneling barrier at the emitter/vacuum interface. The transmission probability D for this barrier can be written D H P exp[-G], where P is a transmission pre-factor and G is the JWKB exponent or "barrier strength". The influence of theoretical effects on the barrier form and on D can be illustrated by plotting (-G) and/or lnD as functions of reciprocal field or voltage. This is a specialized form of Fowler-Nordheim (FN) plot. Its usefulness as a pedagogical tool has perhaps been under-appreciated; it may also prove useful for discussing the issue of what causes curvature in FN plots. © 2012 IEEE.
Forbes R, Deane J, Shail R (2007) Exact mathematical solution for the principal field emission correction function v used in Standard Fowler-Nordheim theory, Technical Digest of the 20th International Vacuum Nanoelectronics Conference, IVNC 07 pp. 149-150
Forbes RG (1987) Training in the use of a full-custom design system, pp. 45-47 IEE
Forbes RG (1999) Refining the application of Fowler-Nordheim theory, ULTRAMICROSCOPY 79 (1-4) pp. 11-23 ELSEVIER SCIENCE BV
FORBES RG (1984) ON THE SHAPE OF A LIQUID-METAL FIELD-ION EMITTER, JOURNAL DE PHYSIQUE 45 (NC9) pp. 161-166 EDITIONS PHYSIQUE
Forbes RG (1996) Charged surfaces, field adsorption, and appearance-energies: An unsolved challenge, JOURNAL DE PHYSIQUE IV 6 (C5) pp. 25-30 EDITIONS PHYSIQUE
FORBES RG, MAIR GLR, LJEPOJEVIC NN, LIU WB (1995) NEW UNDERSTANDINGS IN THE THEORY OF LIQUID-METAL ION SOURCES, APPLIED SURFACE SCIENCE 87-8 (1-4) pp. 99-105 ELSEVIER SCIENCE BV
FORBES RG (1995) FIELD EVAPORATION THEORY - A REVIEW OF BASIC IDEAS, APPLIED SURFACE SCIENCE 87-8 (1-4) pp. 1-11 ELSEVIER SCIENCE BV
Wang RLC, Kreuzer HJ, Forbes RG (1996) Field adsorption of helium and neon on metals: An integrated theory, SURFACE SCIENCE 350 (1-3) pp. 183-205 ELSEVIER SCIENCE BV
LIU WB, FORBES RG (1995) MODELING THE LINK BETWEEN EMISSION CURRENT AND LMIS CUSP LENGTH, APPLIED SURFACE SCIENCE 87-8 (1-4) pp. 122-126 ELSEVIER SCIENCE BV
Forbes RG (1974) AN ALTERNATIVE THEORETICAL APPROACH TO FIELD EVAPORATION RATE SENSITIVITIES, SURF SCI 46 (2) pp. 577-601 ELSEVIER SCIENCE BV
Forbes RG (1970) Field ion microscopy at very low temperatures,
Forbes RG, Deane JHB (2013) Progress with developing theory for fowler-nordheim plot interpretation, 2013 26th International Vacuum Nanoelectronics Conference, IVNC 2013
The work described in this conference talk follows up recent work on the development of a test for lack of field emission orthodoxy. There are three stages of discussion involved. First, the results of applying the test to 17 selected published FN plots are reported. About half fail the test, showing that related published field enhancement factor (FEF) values are unreliable. In several cases, this failure is probably related to plot 'saturation' associated with series resistance. Thus, second, we have explored how to calculate a 'slope correction factor for the case of constant series resistance'. This can be done, but the outcome is not useful. Third, we briefly outline other conceivable routes to more accurate extraction or characterization of 'true physical FEFs', and suggest that systematic simulation experiments on all or some of these might be of interest. © 2013 IEEE.
FORBES RG, WAFI MK (1980) THE FIELD ADSORPTION OF HELIUM IN ARRAY-TYPE MODELS, ULTRAMICROSCOPY 5 (2) pp. 265-265 ELSEVIER SCIENCE BV
Forbes RG (2001) Low-macroscopic-field electron emission from carbon films and other electrically nanostructured heterogeneous materials: hypotheses about emission mechanism, SOLID-STATE ELECTRONICS 45 (6) pp. 779-808 PERGAMON-ELSEVIER SCIENCE LTD
Forbes RG, Xanthakis JP (2007) Field penetration into amorphous-carbon films: consequences for field-induced electron emission, SURFACE AND INTERFACE ANALYSIS 39 (2-3) pp. 139-145 JOHN WILEY & SONS LTD
Forbes RG (2009) Proposal to replace Fowler-Nordheim plots by Millikan-Lauritsen plots as the basic method of analysing experimental field emission data, Technical Digest - 2009 22nd International Vacuum Nanoelectronics Conference, IVNC 2009 pp. 13-14
Forbes RG (2003) Theories of low-macroscopic-field electron emission, TECHNICAL DIGEST OF THE 16TH INTERNATIONAL VACUUM MICROELECTRONICS CONFERENCE pp. 3-3 JAPAN SOC PROMOT SCI
FORBES RG, CHIBANE K (1986) DERIVATION OF AN ACTIVATION-ENERGY FORMULA IN THE CONTEXT OF CHARGE DRAINING, JOURNAL DE PHYSIQUE 47 (C-7) pp. 65-70 EDITIONS PHYSIQUE
Forbes RG (2013) Conceptual error in the definition of the term "voltage" in the international standard for electromagnetism, and related implications for the theory of patch fields and electron emission, 2013 26th International Vacuum Nanoelectronics Conference, IVNC 2013
This conference talk serves two purposes. By considering a thought experiment involving two connected wires with different work functions, it shows that the 'practical voltage' measured by a galvanometer-type voltmeter (or modern equivalents) does NOT coincide with the quantity 'IEC voltage' defined in the International Standard for Electromagnetism and related documents. The probable cause of this discrepancy and some other related issues will be discussed. Further study of the thought experiment leads to a more complete explanation of patch fields, and insights into the theory of electron emission, and into the behavior of charged entities near metal surfaces that exhibit areas of different local work function. © 2013 IEEE.
Forbes RG (2001) Theory of field electron emission from free-electron conductors, pp. 62-83 Academprint
FORBES RG (1980) APPEARANCE ENERGIES FOR TUNGSTEN IONS FIELD-EVAPORATED FROM IONIC BONDING STATES, JOURNAL OF PHYSICS D-APPLIED PHYSICS 13 (7) pp. 1357-1363 IOP PUBLISHING LTD
Forbes RG (2009) Use of Millikan-Lauritsen plots, rather than Fowler-Nordheim plots, to analyze field emission current-voltage data, JOURNAL OF APPLIED PHYSICS 105 (11) ARTN 114313 AMER INST PHYSICS
Forbes RG, Deane JHB (2010) Comparison of approximations for the principal Schottky-Nordheim barrier function v(f), and comments on Fowler-Nordheim plots, JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B 28 (2) pp. C2A33-C2A42 A V S AMER INST PHYSICS
LAWDAY GL, FORBES RG (1989) ASIC DESIGN, THE SOLO 1000 TOOL SET, AND BTEC COURSES, INTERNATIONAL JOURNAL OF ELECTRICAL ENGINEERING EDUCATION 26 (1-2) pp. 30-37 MANCHESTER UNIV PRESS
Forbes RG (2012) Recent progress in reshaping the theory of orthodox field electron emission, Technical Digest - 25th International Vacuum Nanoelectronics Conference, IVNC 2012 pp. 22-23
As part of a continuing attempt to build a more coherent scientific structure for the theory of field-assisted electron emission, and in particular for the interpretation of measured current-voltage data, this paper provides an overview of recent progress in what is proving to be a very messy and complicated task. © 2012 IEEE.
Forbes RG (2016) Physical electrostatics of small field emitter arrays/clusters, JOURNAL OF APPLIED PHYSICS 120 (5) ARTN 054302 AMER INST PHYSICS
Morton E, Taylor D, Patel DC, Forbes RG (1996) Mixed signal ASIC for amorphous silicon pixellated array X-ray imaging system, pp. 161-166 Technical University of Lodz
Forbes RG (1979) In defence of seven dimensions, International Journal of Mechanical Engineering Education 7 pp. 203-204
FORBES RG, MAIR GLR (1982) ARGUMENTS ABOUT EMITTER SHAPE FOR A LIQUID-METAL FIELD-ION EMISSION SOURCE, JOURNAL OF PHYSICS D-APPLIED PHYSICS 15 (11) pp. L153-L158 IOP PUBLISHING LTD
Forbes RG, Deane JHB, Hamid N, Sim HS (2004) Extraction of emission area from Fowler-Nordheim plots, JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B 22 (3) pp. 1222-1226 A V S AMER INST PHYSICS
Forbes RG, Mair GLR (2008) Liquid metal ion sources, In: ORLOFF J (eds.), HANDBOOK OF CHARGED PARTICLE OPTICS, 2nd Edition CRC Press
Forbes RG (2008) Physics of generalized Fowler-Nordheim-type equations, JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B 26 (2) pp. 788-793 A V S AMER INST PHYSICS
Forbes RG, Deane JHB (2005) Fowler-nordheim parameters for sharply-curved emitters, Technical Digest of the 18th International Vacuum Nanoelectronics Conference, IVNC 2005 2005 pp. 109-110
CHIBANE K, FORBES RG (1984) ON THE USE OF CURVE INTERSECTION FORMALISMS IN FIELD EVAPORATION THEORY, JOURNAL DE PHYSIQUE 45 (NC9) pp. 99-104 EDITIONS PHYSIQUE
Peng J, Li Z, He C, Chen G, Wang W, Deng S, Xu N, Zheng X, Chen G, Edgcombe CJ, Forbes RG (2008) The roles of apex dipoles and field penetration in the physics of charged, field emitting, single-walled carbon nanotubes, JOURNAL OF APPLIED PHYSICS 104 (1) ARTN 014310 AMER INST PHYSICS
Forbes RG (1977) The mole??interpreting it, Education in Chemistry 14
Forbes RG (2012) Extraction of emission parameters for large-area field emitters, using a technically complete FowlerNordheim-type equation, Nanotechnology 23 (9)
In papers on cold field electron emission from large-area field emitters (LAFEs), it has become widespread practice to publish a misleading FowlerNordheim-type (FN-type) equation. This equation over-predicts the LAFE-average current density by a large highly variable factor thought to usually lie between 10 3 and 10 9. This equation, although often referenced to FNs 1928 paper, is a simplified equation used in undergraduate teaching, does not apply unmodified to LAFEs and does not appear in the 1928 paper. Technological LAFE papers often do not cite any theoretical work more recent than 1928, and often do not comment on the discrepancy between theory and experiment. This usage has occurred widely, in several high-profile American and UK applied-science journals (including Nanotechnology), and in various other places. It does not inhibit practical LAFE development, but can give a misleading impression of potential LAFE performance to non-experts. This paper shows how the misleading equation can be replaced by a conceptually complete FN-type equation that uses three high-level correction factors. One of these, or a combination of two of them, may be useful as an additional measure of LAFE quality; this paper describes a method for estimating factor values using experimental data and discusses when it can be used. Suggestions are made for improved engineering practice in reporting LAFE results. Some of these should help to prevent situations arising whereby an equation appearing in high-profile applied-science journals is used to support statements that an engineering regulatory body might deem to involve professional negligence. © 2012 IOP Publishing Ltd.
Forbes RG (2000) Theory and modelling of field-induced electron emission, Materials Research Society Symposium - Proceedings 621
This paper addresses issues in the theory of field-induced electron emission. First, it summarises our present understanding of the theory of Fowler-Nordheim (FN) plots, and shows the relationship between a recent precise (in standard FN theory) approach to the interpretation of the FN-plot intercept and older approximate approaches. Second, it comments on the interpretation of FN plots taken from semiconductor field emitters. Third, it summarises the main points of a recent hypothesis about the mechanism of field-induced emission from carbon- based films and other electrically nanostructured heterogeneous (ENH) materials. Weaknesses in previous hypotheses are noted. It is hypothesised that thin films of all ENH materials, when deposited on a conducting substrate, will emit electrons in appropriate circumstances. Such films emit electrons at low macroscopic fields because they contain conducting nanostructure inside them: This structure generates sufficient geometrical field enhancement near the film/vacuum interface that more-or-less normal Fowler-Nordheim emission can occur. In connection with experiments on amorphous carbon films carried out by a group in Fribourg, it is shown that nanostructure of the size measured by scanning probe techniques should be able to generate field enhancement of the size measured in field electron spectroscopy experiments. This result provides a quantitative corroboration of other work suggesting that emission from amorphous carbon films is primarily clue to geometrical field enhancement by nanostructures inside the film. Some counter-arguments to the internal-field-enhancement hypothesis are considered and disposed of. Some advantages of ENH materials as broad-area field emission electron sources are noted; these include control of material design.
Forbes RG (2008) On the need for a tunneling pre-factor in Fowler-Nordheim tunneling theory, JOURNAL OF APPLIED PHYSICS 103 (11) ARTN 114911 AMER INST PHYSICS
Forbes RG (2009) Theories of field emission from graphene based on thin-slab and atomic-array models, Technical Digest - 2009 22nd International Vacuum Nanoelectronics Conference, IVNC 2009 pp. 99-100
MAIR GLR, FORBES RG (1992) AN ANALYTICAL CALCULATION OF LMIS CUSP LENGTH, SURFACE SCIENCE 266 (1-3) pp. 180-184 ELSEVIER SCIENCE BV
Forbes RG (1976) A fundamental proposal concerning the "mole", Education in Chemistry 13
FORBES RG (1986) FIELD-ION ENERGY DEFICITS IN THE ATOM PROBE FIM, JOURNAL DE PHYSIQUE 47 (C-2) pp. 31-36 EDITIONS PHYSIQUE
FORBES RG (1982) AN EVAPORATION-FIELD FORMULA INCLUDING THE REPULSIVE ION-SURFACE INTERACTION, JOURNAL OF PHYSICS D-APPLIED PHYSICS 15 (7) pp. L75-L77 IOP PUBLISHING LTD
FORBES RG (1978) FIELD EVAPORATION THEORY - ATOMIC-JUG FORMALISM, SURFACE SCIENCE 70 (1) pp. 239-254 ELSEVIER SCIENCE BV
Forbes RG (1978) Field ionization and surface plasmons: an alternative theoretical formulation, Nederlands Tidjschrift voor Vacuumtechniek 16 pp. 268-268
FORBES RG (1982) EXPERIMENTAL SUPPORT FOR A GOMER-TYPE ESCAPE MECHANISM AND HEAVY-ION TUNNELLING IN FIELD EVAPORATION, JOURNAL OF PHYSICS D-APPLIED PHYSICS 15 (11) pp. L149-L152 IOP PUBLISHING LTD
Forbes RG, Deane JHB, Fischer A, Mousa MS (2013) Illustrating field emission theory by using Lauritsen plots of transmission probability and barrier strength, Journal of Vacuum Science and Technology B:Nanotechnology and Microelectronics 31 (2)
This technical note relates to the theory of cold field electron emission (CFE). It starts by suggesting that, to emphasize common properties in relation to CFE theory, the term "Lauritsen plot" could be used to describe all graphical plots made with the reciprocal of barrier field (or the reciprocal of a quantity proportional to barrier field) on the horizontal axis. It then argues that Lauritsen plots related to barrier strength (G) and transmission probability (D) could play a useful role in discussion of CFE theory. Such plots would supplement conventional Fowler-Nordheim (FN) plots. All these plots would be regarded as particular types of Lauritsen plot. The Lauritsen plots of -G and lnD can be used to illustrate how basic aspects of FN tunneling theory are influenced by the mathematical form of the tunneling barrier. These, in turn, influence local emission current density and emission current. Illustrative applications used in this note relate to the well-known exact triangular and Schottky-Nordheim barriers, and to the Coulomb barrier (i.e., the electrostatic component of the electron potential energy barrier outside a model spherical emitter). For the Coulomb barrier, a good analytical series approximation has been found for the barrier-form correction factor; this can be used to predict the existence (and to some extent the properties) of related curvature in FN plots. © 2013 American Vacuum Society.
Forbes RG (1977) Some new ideas in field-ion theory, pp. 387-390
Forbes RG (2007) The physics of generalized Fowler-Nordheim-type equations, Technical Digest of the 20th International Vacuum Nanoelectronics Conference, IVNC 07 pp. 44-45
FORBES RG (1982) ELECTRO-THERMODYNAMIC CYCLES APPLIED TO IONIC POTENTIALS AND TO FIELD EVAPORATION, JOURNAL OF PHYSICS D-APPLIED PHYSICS 15 (7) pp. 1301-1322 IOP PUBLISHING LTD
Forbes RG (2010) Thin-slab model for field electron emission, JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B 28 (2) pp. C2A43-C2A49 A V S AMER INST PHYSICS
Forbes RG (2001) Update on analysis of Fowler-Nordheim plots from nonmetallic emitters, IVMC 2000: PROCEEDINGS OF THE 14TH INTERNATIONAL VACUUM MICROELECTRONICES CONFERENCE pp. 95-95 IEEE
LJEPOJEVIC NN, FORBES RG (1992) A COMPARISON OF THE NUMERICAL AND ANALYTICAL TREATMENTS OF A LIQUID-METAL ION-SOURCE, SURFACE SCIENCE 266 (1-3) pp. 176-179 ELSEVIER SCIENCE BV
FORBES RG (1981) WAVE-MECHANICAL THEORY OF FIELD-IONIZATION AND FIELD-ION ENERGY-DISTRIBUTIONS, PROGRESS IN SURFACE SCIENCE 10 (2) pp. 249-285 PERGAMON-ELSEVIER SCIENCE LTD
Forbes RG (2005) How the world first saw atoms: an outline of how field ion imaging works, Microscopy and Microanalysis 11 (Supplement 2) pp. 860-861
Forbes RG (1977) Re-exploration of the concepts of work function and ionization energy, pp. 433-436
Forbes RG (1982) The escape mechanism in low-temperature field evaporation, pp. 11-18 Almqvist & Wiskell
Forbes RG, Ljepojevic NN (1991) Electrohydrodynamics, liquid metal ion sources, and electrostatic atomisation, pp. 206-211
BISWAS RK, FORBES RG (1982) THEORETICAL ARGUMENTS AGAINST THE MULLER-SCHOTTKY MECHANISM OF FIELD EVAPORATION, JOURNAL OF PHYSICS D-APPLIED PHYSICS 15 (7) pp. 1323-1338 IOP PUBLISHING LTD
FORBES RG (1993) A COMMENT ON THE RELATIONSHIP BETWEEN EMISSION FIELD AND TIP RADIUS FOR A LIQUID-METAL ION-SOURCE, APPLIED SURFACE SCIENCE 67 (1-4) pp. 9-12 ELSEVIER SCIENCE BV
Forbes RG (1999) Use of a spreadsheet for Fowler-Nordheim equation calculations, JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B 17 (2) pp. 534-541 AMER INST PHYSICS
Forbes RG (1977) Atomic polarizability values in the SI system, SURF SCI 64 (1) pp. 367-371 ELSEVIER SCIENCE BV
Forbes RG, Ganetsos T, Mair GLR, Suvorov VG (2004) Liquid metal ion sources at Aston in the 1980s and what followed, Proceedings of the Royal Microscopical Society 39 pp. 218-226
Forbes RG, Deane JHB (2007) Reformulation of the standard theory of Fowler-Nordheim tunnelling and cold field electron emission, PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES 463 (2087) pp. 2907-2927 ROYAL SOC
Deane JHB, Forbes RG (2008) The formal derivation of an exact series expansion for the principal Schottky-Nordheim barrier function v, using the Gauss hypergeometric differential equation, JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL 41 (39) ARTN 395301 IOP PUBLISHING LTD
Fischer A, Mousa MS, Forbes RG (2013) Influence of barrier form on Fowler-Nordheim plot analysis, Journal of Vacuum Science and Technology B:Nanotechnology and Microelectronics 31 (3)
Recent research has described an improved method of Fowler-Nordheim (FN) plot analysis, based on the definition and evaluation of a slope correction factor and a new form of intercept correction factor. In this improved approach, there exists a basic approximation that neglects certain terms in the general theory, and focuses on the influence of the form of the tunneling barrier on the values of basic slope (à B) and intercept (Á B) correction factors. Simple formulae exist that allow these to be evaluated numerically for a barrier of arbitrary well-behaved form. This paper makes an initial exploration of the effects of barrier form on FN plot analysis. For a planar emitter, two models for the correlation-and-exchange (CE) potential energy (PE) are used. For the Schottky-Nordheim barrier, it is shown that numerical and analytical approaches generate equivalent results. This agreement supports the validity of the numerical methods used. Comparisons with results for the Cutler-Gibbons barrier show that small differences in the assumed CE PE make little difference to values of à B and Á B. Schottky's planar image PE has then been used, in conjunction with the electrostatic PE variation associated with a spherical emitter model, to explore the influence of apex radius r a on correction-factor values, for values of r a e 20 nm. Both à B and Á B increase significantly as r a decreases, especially Á B. At low values of barrier field F, à B depends approximately linearly on 1/F, with a slope that depends on r a. Suggestions are made for how the exploratory work described in this paper might be extended. © 2013 American Vacuum Society.
FORBES RG, CHIBANE K (1982) A FRESH LOOK AT THE ELECTRIC-FIELD DEPENDENCE OF SURFACE-ATOM BINDING-ENERGY, SURFACE SCIENCE 121 (2) pp. 275-289 ELSEVIER SCIENCE BV
Forbes RG (2005) A look at the basic physics of cold field electron emission, Technical Digest of the 18th International Vacuum Nanoelectronics Conference, IVNC 2005 2005 pp. 1-2
FORBES RG (1986) THE PHYSICS OF LIQUID-METAL FIELD-ION SOURCE, VACUUM 36 (11-12) pp. 1020-1020 PERGAMON-ELSEVIER SCIENCE LTD
Miller MK, Forbes RG (2009) Atom probe tomography, MATERIALS CHARACTERIZATION 60 (6) pp. 461-469 ELSEVIER SCIENCE INC
Fischer A, Mousa MS, Deane JHB, Forbes RG (2013) The effect of barrier form on slope and intercept correction factors for curved emitters: Development of some enabling theory, 2013 26th International Vacuum Nanoelectronics Conference, IVNC 2013
The work described in this conference poster follows up recent work on the interpretation of Fowler-Nordheim (FN) plots. It puts in place some enabling theory that should allow further development of plot interpretation theory, in the context of the sphere-on-othogonal-cone (SOC) emitter model. This model is expected to be more suitable, for small-apex-radius emitters, than the spherical-emitter (SPH) model. First, this report shows (as expected) that use of the spherical image-potential-energy formula, rather than the planar formula, appears to make little difference to the values of calculated parameters. Second, values of the exponent n (in the SOC model) are tabulated as a function of internal cone half-angle. Third, an expression is derived for the electrostatic component of electron motive energy, in the SOC model. Finally, the results of a sample calculation are presented. This compares values of the slope correction factor à for the SPH and SOC models, for emitter-radius values 20 nm and 5 nm. As expected, the results for the two models are similar for 20 nm, but diverge as apex radius decreases. © 2013 IEEE.
Forbes RG (2012) Scaled form for kernel Fowler-Nordheim-type expression based on the Schottky-Nordheim barrier, and test for orthodoxy of field electron emission, Technical Digest - 25th International Vacuum Nanoelectronics Conference, IVNC 2012 pp. 282-283
This conference paper supports an overview presented elsewhere in this conference, by setting out detailed theory about the concept of "kernel current density", and about the development of a simple numerical test for (lack of) emission orthodoxy. The test can be applied to any form of linear (or nearly linear) Fowler-Nordheim plot. © 2012 IEEE.
FORBES RG (1979) BASIC WAVE-MECHANICAL THEORY OF FIELD-ION ENERGY-DISTRIBUTIONS, ULTRAMICROSCOPY 4 (3) pp. 372-372 ELSEVIER SCIENCE BV
FORBES RG (1982) NEW ACTIVATION-ENERGY FORMULAS FOR CHARGE-EXCHANGE TYPE MECHANISMS OF FIELD EVAPORATION, SURFACE SCIENCE 116 (2) pp. L195-L201 ELSEVIER SCIENCE BV
Forbes RG (2010) Simple derivation of the formula for Sommerfeld supply density used in electron-emission physics and limitations on its use, Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures 28 (6) pp. 1326-1329
Fischer A, Mousa MS, Forbes RG (2010) P1-27: Influence of improved surface potential-energy model on CFE characteristics and related slope and intercept correction factors, Proceedings of 23rd International Vacuum Nanoelectronics Conference, IVNC 2010 pp. 79-79
This poster explores the influence of an improved surface potential energy model on the predicted characteristics of cold field electron emission. We explore effects on the shape of Fowler-Nordheim plots, and on the values of slope and intercept correction functions.
Forbes RG (2012) Resolving power of the field electron and field ion imaging processes, Technical Digest - 25th International Vacuum Nanoelectronics Conference, IVNC 2012 pp. 286-287
This conference paper reports the interim conclusions of a re-examination of the theory of the resolving power of the field electron and field ion microscopes. It argues that existing theory contains multiple errors and needs to be completely replaced. Progress made is reported. The nature of problems remaining to be solved is briefly discussed. © 2012 IEEE.
Forbes RG, Djuric Z (1996) Progress in understanding liquid-metal ion source operation, IVMC '96 - 9TH INTERNATIONAL VACUUM MICROELECTRONICS CONFERENCE, TECHNICAL DIGEST pp. 468-472 I E E E
Forbes RG (2008) Appendix to "Coulomb interactions in Ga LMIS" by Radlicka and Lencova, ULTRAMICROSCOPY 108 (5) pp. 455-457 ELSEVIER SCIENCE BV
Forbes RG (2011) Comments on discrepancies in the Fowler and Nordheim 1928 paper, Proceedings - IVNC 2011: 2011 24th International Vacuum Nanoelectronics Conference pp. 113-114
This paper records known discrepancies in the much cited paper of Fowler and Nordheim [Proc. Roy. Soc. London, vol. A 119, pp. 173-191 (1928)].
FORBES RG (1989) ON CHARGED-SURFACE MODELS AND THE ORIGIN OF FIELD ADSORPTION, SURFACE SCIENCE 223 (1-2) pp. 326-352 ELSEVIER SCIENCE BV
Forbes RG (1971) Field ion image formation, Nature Physical Science 230 pp. 165-166
Forbes RG (1982) The derivation of surface atomic information from field evaporation experiments,
Forbes RG (1995) A new magnetic vocabulary, Physics World 8 pp. 21-22
FORBES RG, WAFI MK (1980) AN ARRAY MODEL FOR THE FIELD ADSORPTION OF HELIUM ON TUNGSTEN (111), SURFACE SCIENCE 93 (1) pp. 192-212 ELSEVIER SCIENCE BV
Forbes RG, Fischer A, Mousa MS, Fischer A (2012) New type of intercept correction factor for Fowler-Nordheim plots, Technical Digest - 25th International Vacuum Nanoelectronics Conference, IVNC 2012 pp. 288-289
This paper defines a new type of intercept correction factor for use in connection with the tangent method of analyzing Fowler-Nordheim plots. Unlike the factor previously used, the new factor is well defined and can be evaluated precisely for simple barrier models. Theory using the new factor is intended to replace existing theory. Applications will be presented elsewhere. © 2012 IEEE.
Forbes RG (2007) Analysis of planar field-stimulated vacuum space-charge using a dimensionless equation, 2007 IEEE 20TH INTERNATIONAL VACUUM NANOELECTRONICS CONFERENCE pp. 133-134 IEEE
Forbes RG (2007) Tutorial lecture on the theory of cold field electron emission, 2007 IEEE 20TH INTERNATIONAL VACUUM NANOELECTRONICS CONFERENCE pp. 34-35 IEEE
Forbes RG, Liu WB (1995) Electrohydrodynamic theory of liquid metal ion sources, ELECTROSTATICS 1995 143 pp. 193-200 IOP PUBLISHING LTD
Forbes RG (2013) Use of a spreadsheet to test for lack of field emission orthodoxy, 2013 26th International Vacuum Nanoelectronics Conference, IVNC 2013
This conference poster provides support to presentations made at the International Vacuum Nanoelectronics Conferences in 2012 and 2013. So-called 'orthodox' field electron emission (orthodox FE) is specified by a set of physical and mathematical assumptions convenient for the purposes of analyzing current-voltage or equivalent data plotted as a Fowler-Nordheim plot. The development of a numerical test for lack of field emission orthodoxy, and the results of its application, are described elsewhere. The test is based on extracting values of scaled barrier field (f-values) from FN plots, and comparing these with the range of values expected if emission is orthodox. If emission is not orthodox, then the values of certain emitter characterization parameters (such as field enhancement factors), commonly derived from FN plots by simple formulae, may be unreliable. The spreadsheet described here is available free from the author, and provides a quick and easy way of extracting f-values from FN plots. This should take about 10 minutes per plot. The poster describes the input data needed for the spreadsheet, and how the spreadsheet operates. © 2013 IEEE.
Forbes RG (1972) A theory of field ion imaging: II - On the origin of site-current variations, Journal of Microscopy 96 pp. 63-75
Forbes RG (1997) Understanding how the liquid-metal ion source works, VACUUM 48 (1) pp. 85-97 PERGAMON-ELSEVIER SCIENCE LTD
Mayer A, Deane JHB, Forbes RG (2010) P1-28: Use, in Fowler-Nordheim-type equations, of accurate solution of the schrödinger equation for the schottky-nordheim barrier, Proceedings of 23rd International Vacuum Nanoelectronics Conference pp. 80-81
The Schottky-Nordheim (SN) barrier is used in the "standard" theory of cold field electron emission (CFE) developed by Murphy and Good in 1956. For the SN barrier, it is mathematically impossible to derive analytical solutions of the Schro?dinger equation in terms of the common functions of mathematical physics. Existing simple analytical CFE theories are based on so-called "quasi-classical" quantum-mechanical methods, typically a JWKB-type approximation. Recently, numerical methods have been applied to the SN barrier that should generate accurate solutions for the transmission coefficient DT. This poster is a "tidy-up" exercise that explores quantitatively how these accurate solutions put correction factors into Fowler-Nordheim-type equations.
Forbes RG (1976) Comments on "intrinsic energy losses of field evaporated ions", J PHYS D APPL PHYS 9 (15) pp. L191-L193 IOP PUBLISHING LTD
Forbes RG (1985) The concept: Amount of Substance, School Science Review 66 pp. 787-788
Forbes RG, Kreuzer HJ, Wang RLC (1996) On the theory of helium field adsorption, APPLIED SURFACE SCIENCE 94-5 pp. 60-67 ELSEVIER SCIENCE BV
BISWAS RK, FORBES RG (1988) A CLASSIFICATION OF TESTS AGAINST THE MULLER ESCAPE MECHANISM, JOURNAL DE PHYSIQUE 49 (C-6) pp. 11-16 EDITIONS PHYSIQUE
Forbes RG (2001) Field-induced electron emission from electrically nanostructured heterogeneous (ENH) materials, ULTRAMICROSCOPY 89 (1-3) pp. 7-15 ELSEVIER SCIENCE BV
Forbes RG (1976) ON THE NEED FOR NEW MEASUREMENTS OF FIELD-ION APPEARANCE POTENTIAL FOR HELIUM, INT J MASS SPECTROM 21 (3-4) pp. 417-420 ELSEVIER SCIENCE BV
Forbes RG (1999) The electrical surface as centroid of the surface-induced charge, ULTRAMICROSCOPY 79 (1-4) pp. 25-34 ELSEVIER SCIENCE BV
FORBES RG, LJEPOJEVIC NN (1992) LIQUID-METAL ION-SOURCE THEORY - ELECTROHYDRODYNAMICS AND EMITTER SHAPE, SURFACE SCIENCE 266 (1-3) pp. 170-175 ELSEVIER SCIENCE BV
FORBES RG (1978) NEGATIVE WORK-FUNCTION CORRECTION AT A POSITIVELY-CHARGED SURFACE, JOURNAL OF PHYSICS D-APPLIED PHYSICS 11 (14) pp. L161-L164 IOP PUBLISHING LTD
Forbes R (2009) Use of the concept "area efficiency of emission" in equations describing field emission from large-area electron sources, JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B 27 (3) pp. 1200-1203 A V S AMER INST PHYSICS
Forbes RG (2006) Comments on the JWKB approximation, IVNC and IFES 2006 - Technical Digest - l9th International Vacuum Nanoelectronics Conference and 50th International Field Emission Symposium pp. 11-12
Forbes RG, Fischer A, Mousa MS (2013) Improved approach to Fowler-Nordheim plot analysis, Journal of Vacuum Science and Technology B:Nanotechnology and Microelectronics 31 (2)
This article introduces an improved approach to Fowler-Nordheim (FN) plot analysis, based on a new type of intercept correction factor. This factor is more cleanly defined than the factor previously used. General enabling theory is given that applies to any type of FN plot of data that can be fitted using a FN-type equation. Practical use is limited to emission situations where slope correction factors can be reliably predicted. By making a series of well-defined assumptions and approximations, it is shown how the general formulas reduce to provide an improved theory of orthodox FN-plot data analysis. This applies to situations where the circuit current is fully controlled by the emitter characteristics, and tunneling can be treated as taking place through a Schottky-Nordheim (SN) barrier. For orthodox emission, good working formulas make numerical evaluation of the slope correction factor and the new intercept correction factor quick and straightforward. A numerical illustration, using simulated emission data, shows how to use this improved approach to derive values for parameters in the full FN-type equation for the SN barrier. Good self-consistency is demonstrated. The general enabling formulas also pave the way for research aimed at developing analogous data-analysis procedures for nonorthodox emission situations. © 2013 American Vacuum Society.
Cook BM, Forbes RG (1989) ISIS in the educational environment, In: Massara RE, Engineers IOE (eds.), Design & test techniques for VLSI & WSI circuits 7 pp. 109-118 Peter Peregrinus
Silva SRP, Forbes RG (1998) Controlling mechanisms for field-induced electron emission from diamond-like carbon films, ULTRAMICROSCOPY 73 (1-4) pp. 51-57 ELSEVIER SCIENCE BV
Forbes RG (1978) Amount of substance: An alternative proposal, Physics Education 13 (5) pp. 269-272
CHIBANE K, FORBES RG (1982) THE TEMPERATURE-DEPENDENCE OF EVAPORATION FIELD FOR GOMER-TYPE FIELD-EVAPORATION MECHANISMS, SURFACE SCIENCE 122 (2) pp. 191-215 ELSEVIER SCIENCE BV
FORBES RG (1986) TOWARDS A UNIFIED THEORY OF HELIUM FIELD-IONIZATION PHENOMENA, JOURNAL DE PHYSIQUE 47 (C-2) pp. 3-10 EDITIONS PHYSIQUE
Forbes RG (1997) On the problem of establishing the location of the electrical surface (image plane) for a tungsten field emitter, ZEITSCHRIFT FUR PHYSIKALISCHE CHEMIE-INTERNATIONAL JOURNAL OF RESEARCH IN PHYSICAL CHEMISTRY & CHEMICAL PHYSICS 202 pp. 139-161 R OLDENBOURG VERLAG
Forbes RG (1982) The seventh SI quantity, Education in Chemistry 19
FORBES RG (1981) PROGRESS WITH THE THEORY OF NOBLE-GAS FIELD ADSORPTION, VACUUM 31 (10-1) pp. 567-570 PERGAMON-ELSEVIER SCIENCE LTD
Forbes RG, Deane JHB (2011) Progress in securing the foundations of field-assisted electron emission theory, Proceedings of 24th International Vacuum Nanoelectronics Conference pp. 1-2
This paper presents the results of a re-examination of the wave-mechanical theory of electron emission across an exact triangular barrier. This is a fourth-generation treatment of a problem first addressed by Fowler and Nordheim in 1928, subsequently by other researchers. The outcome is a transparent derivation of an exact general analytical formula (previously found by Jensen) and the identification of numerous special cases in which specific approximations to the general formula apply.
Forbes RG (1991) The physicists' Amount too, School Science Review 73 pp. 133-133
Forbes RG (1972) Reply to "Comments on field ion image formation", Nature Physical Science 239 pp. 15-16
Forbes RG, Li Z (2011) Emission reference level: A missing concept in emission theory, Proceedings of 24th International Vacuum Nanoelectronics Conference pp. 121-122
This paper introduces the physical concept of Emission Reference Level (ERL) and relates it to the already-used concept of reference barrier height HR. The ERL is a concept particularly helpful for small emitters, where quantum confinement effects occur, but can also be used to clarify energy diagrams drawn to explain field electron emission from bulk emitters.
Mair GLR, Forbes RG, Latham RV, Mulvey T (1983) ENERGY SPREAD MEASUREMENTS ON A LIQUID METAL ION SOURCE., pp. 171-178 Academic Press
Forbes RG (2010) P2-31: Simple derivation of formula for sommerfeld supply density, Proceedings of 23rd International Vacuum Nanoelectronics Conference pp. 181-182
This poster presents a simple derivation of the result that (for a large free-electron conductor) the electron supply density is constant in energy-space and is given by the Sommerfeld supply density zS, and also proves the formula for zS. This result is the best starting point for deriving Richardson-Schottky-type and Fowler-Nordheim-type equations. For small emitters the supply density is not constant in energy-space; consequently, emission from small emitters is not well described by these equations.
Forbes RG (2008) Gas Field Ionization Sources, In: ORLOFF J (eds.), HANDBOOK OF CHARGED PARTICLE OPTICS 3 CRC Press
2
Braun E, Forbes RG, Pearson J, Pelmore JM, Latham RV (1978) AN ADVANCED FIELD ELECTRON-EMISSION SPECTROMETER, J PHYS E SCI INSTRUM 11 (3) pp. 222-228 IOP PUBLISHING LTD
Forbes RG (1996) Some comments on the simultaneous desorption of He-3 and He-4, APPLIED SURFACE SCIENCE 94-5 pp. 73-78 ELSEVIER SCIENCE BV
Forbes RG (2012) Screened field enhancement factor for a tall closely spaced array of identical conducting posts and implications for Fowler-Nordheim-type equations, JOURNAL OF APPLIED PHYSICS 111 (9) ARTN 096102 AMER INST PHYSICS
Forbes RG (2010) 5.4: Analysis of experimental field emission current-voltage characteristics (especially those from carbon nanotubes), Proceedings of 23rd International Vacuum Nanoelectronics Conference pp. 92-93
This paper discusses alternative physical explanations of experimental field emission current-voltage characteristics (particularly those from carbon-nanotube arrays), and re-examines the existing theory of Fowler-Nordheim plots.
Forbes RG (2001) Is uniform electron emission possible at low macroscopic fields?, IVMC 2000: PROCEEDINGS OF THE 14TH INTERNATIONAL VACUUM MICROELECTRONICES CONFERENCE pp. 79-79 IEEE
FORBES RG, LJEPOJEVIC NN (1989) MODELING OF LIQUID-METAL ION SOURCES, VACUUM 39 (11-12) pp. 1153-1155 PERGAMON-ELSEVIER SCIENCE LTD
Forbes RG (2008) Description of field emission current/voltage characteristics in terms of scaled barrier field values (f-values), JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B 26 (1) pp. 209-213 A V S AMER INST PHYSICS
FORBES RG, COOK BM (1989) THE ROLE OF THE FULL-CUSTOM DESIGN EXERCISE IN TEACHING, INTERNATIONAL JOURNAL OF ELECTRICAL ENGINEERING EDUCATION 26 (1-2) pp. 100-102 MANCHESTER UNIV PRESS
Forbes RG (1998) The field emitter and its applications, ELECTRON pp. 334-340 INST MATERIALS
FORBES RG (1989) ON DIFFERENT TYPES OF DIPOLE-DIPOLE INTERACTION, JOURNAL DE PHYSIQUE 50 (C8) pp. C815-C820 EDITIONS PHYSIQUE
Van Es JJ, Gierak J, Forbes RG, Suvorov VG, Van den Berghe T, Dubuisson P, Monnet I, Septier A (2004) An improved gallium liquid metal ion source geometry for nanotechnology, MICROELECTRONIC ENGINEERING 73-4 pp. 132-138 ELSEVIER SCIENCE BV
FORBES RG, BISWAS RK, CHIBANE K (1982) FIELD EVAPORATION THEORY - A REANALYSIS OF PUBLISHED FIELD SENSITIVITY DATA, SURFACE SCIENCE 114 (2-3) pp. 498-514 ELSEVIER SCIENCE BV
Forbes RG (1999) Field emission: New theory for the derivation of emission area from a Fowler-Nordheim plot, JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B 17 (2) pp. 526-533 AMER INST PHYSICS
FORBES RG (1980) ANOTHER LOOK AT FIELD PENETRATION AND SURFACE-ATOM POLARIZABILITY, ULTRAMICROSCOPY 5 (2) pp. 264-264 ELSEVIER SCIENCE BV
Forbes RG (1980) Reply to comments on: "In defence of seven dimensions", International Journal of Mechanical Engineering Education 8 pp. 99-100
MAIR GLR, MULVEY T, FORBES RG (1984) ENERGY SPREADS IN FIELD EVAPORATION AND LIQUID-METAL ION SOURCES, JOURNAL DE PHYSIQUE 45 (NC9) pp. 179-182 EDITIONS PHYSIQUE
FORBES RG (1991) FURTHER COMMENTS ON FIELD ADSORPTION, SURFACE SCIENCE 246 (1-3) pp. 386-389 ELSEVIER SCIENCE BV
Forbes RG, Bailey AG, Berezin AA, Harpur I, Kleber W, ONeill BC, Vossen C, Hu D, Cunningham S, Touchard G (1995) Analytical techniques - Discussion, ELECTROSTATICS 1995 143 pp. 219-221 IOP PUBLISHING LTD
Forbes RG (1977) Confusion over the avogadro constant, Physics Education 12 (5) pp. 273-274
Forbes RG (1976) Comment on "surface plasmon excitation in field ion emission" by R. Brako and M. `unji?, SURF SCI 60 (1) pp. 260-261 ELSEVIER SCIENCE BV
Forbes RG (2013) Development of a simple quantitative test for lack of field emission orthodoxy, Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 469 (2158)
The orthodox emission hypothesis is a set of physical and mathematical assumptions that permit well-specified analysis of measured current-voltage data relating to field electron emission (FE). If these assumptions are not adequately satisfied, then widely used FE data-analysis methods can generate spurious values for emitter characterization parameters, particularly field enhancement factors (FEFs). This paper describes development of a simple quantitative test for whether FE data are incompatible with the hypothesis. It applies to any geometrical emitter shape and any Fowler-Nordheim (FN) plot type, and involves extracting the related range of scaled-barrier-field values (f values). By analysing historical data, this paper identifies 'apparently reasonable' and 'clearly unreasonable' experimental ranges for f . The historical data, taken between 1926 and 1972, are internally self-consistent. This test is then applied to 19 post-1975 datasets, mainly for various carbon and semiconductor nanostructures. Some extracted f -value ranges (including many carbon results) are apparently reasonable, some are clearly unreasonable. It is shown that if extracted f values are 'unreasonably high', then FEF values extracted by literature methods are spuriously large. New materials and published FN plots that generate particularly high FEF values require testing, and improved data-analysis theory is needed for nonorthodox emitters. A spreadsheet for implementing the test is provided. © 2013 The Author(s).
Forbes RG (1990) What do we mean by work-function ?, pp. 163-173 Kluwer
Forbes RG (2006) Tutorial lecture on field electron emission theory, IVNC and IFES 2006 - Technical Digest - l9th International Vacuum Nanoelectronics Conference and 50th International Field Emission Symposium pp. 559-560
Forbes RG (1972) PROBLEMS IN THE THEORY OF FIELD-ION IMAGING, VACUUM 22 (11) pp. 517-520 PERGAMON-ELSEVIER SCIENCE LTD
Forbes RG (2000) Liquid-metal ion sources and electrosprays operating in cone-jet mode: Some theoretical comparisons and comments, JOURNAL OF AEROSOL SCIENCE 31 (1) pp. 97-120 PERGAMON-ELSEVIER SCIENCE LTD
MAIR GLR, FORBES RG (1991) ANALYTICAL DETERMINATION OF THE DIMENSIONS AND EVOLUTION WITH CURRENT OF THE ION-EMITTING JET IN LIQUID-METAL ION SOURCES, JOURNAL OF PHYSICS D-APPLIED PHYSICS 24 (12) pp. 2217-2221 IOP PUBLISHING LTD
Forbes RG, Deane JHB (2011) Transmission coefficients for the exact triangular barrier: an exact general analytical theory that can replace Fowler & Nordheim's 1928 theory, PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES 467 (2134) pp. 2927-2947 ROYAL SOC
FORBES RG (1979) CONCEPTUAL ERRORS IN THE THEORY OF FIELD ADSORPTION, SURFACE SCIENCE 87 (1) pp. L278-L284 ELSEVIER SCIENCE BV
FORBES RG (1982) A NEW FORMULA FOR PREDICTING LOW-TEMPERATURE EVAPORATION FIELD, APPLIED PHYSICS LETTERS 40 (3) pp. 277-279 AMER INST PHYSICS
Forbes RG (1983) Charged Surfaces and Field Ion Emission. DSc Thesis, University of Aston in Birmingham,
Forbes RG, Edgcombe CJ, Valdre U (2003) Some comments on models for field enhancement, ULTRAMICROSCOPY 95 (1-4) PII S0304-3991(02)00297-8 pp. 57-65 ELSEVIER SCIENCE BV
Forbes RG (1996) Field-ion imaging old and new, APPLIED SURFACE SCIENCE 94-5 pp. 1-16 ELSEVIER SCIENCE BV
Forbes RG, Deane JHB (2009) Comparison of approximations for the principal Schottky-Nordheim barrier function v(f), Technical Digest - 2009 22nd International Vacuum Nanoelectronics Conference, IVNC 2009 pp. 97-98
Forbes R (2009) Use of the concept "area efficiency of emission" in equations describing field emission from large-area electron sources, Technical Digest - 2009 22nd International Vacuum Nanoelectronics Conference, IVNC 2009 pp. 131-132
Forbes RG (1996) The electron energy distribution from very sharp field emitters, IVMC '96 - 9TH INTERNATIONAL VACUUM MICROELECTRONICS CONFERENCE, TECHNICAL DIGEST pp. 58-61 I E E E
FORBES RG (1979) INFLUENCE OF DEPOLARIZATION ON SURFACE-ATOM POLARIZATION ENERGY, SURFACE SCIENCE 82 (2) pp. L620-L624 ELSEVIER SCIENCE BV
Bischoff L, Pilz W, Ganetsos T, Forbes RG, Akhmadaliev C (2007) GaBi alloy liquid metal ion source for microelectronics research, ULTRAMICROSCOPY 107 (9) pp. 865-868 ELSEVIER SCIENCE BV
Forbes RG (1971) Field-ion imaging theory: On the visibility of adsorbates, Surface Science 27 (3) pp. 659-662
Forbes RG (1978) Opinion on SI, Physics Bulletin 29
Forbes RG, Jensen KL (2001) New results in the theory of Fowler-Nordheim plots and the modelling of hemi-ellipsoidal emitters, ULTRAMICROSCOPY 89 (1-3) pp. 17-22 ELSEVIER SCIENCE BV
Forbes RG (2001) Models for low-macroscopic-field electron emission, IVMC 2000: PROCEEDINGS OF THE 14TH INTERNATIONAL VACUUM MICROELECTRONICES CONFERENCE pp. 71-71 IEEE
Forbes RG (2011) Comments on inconsistencies in a recent handbook theory chapter, Proceedings of 24th International Vacuum Nanoelectronics Conference pp. 117-118
This note records theoretical inconsistencies found in the theory chapter of a recent handbook relating to carbon nanotube field electron emitters, suggests corrections and makes some general comments.
FORBES RG (1988) ON THE POSITION OF THE ELECTRICAL REFERENCE SURFACE, VACUUM 38 (4-5) pp. 429-429 PERGAMON-ELSEVIER SCIENCE LTD
LJEPOJEVIC NN, FORBES RG (1995) VARIATIONAL THERMODYNAMIC DERIVATION OF THE FORMULA FOR PRESSURE DIFFERENCE ACROSS A CHARGED CONDUCTING LIQUID SURFACE AND ITS RELATION TO THE THERMODYNAMICS OF ELECTRICAL CAPACITANCE, PROCEEDINGS OF THE ROYAL SOCIETY-MATHEMATICAL AND PHYSICAL SCIENCES 450 (1938) pp. 177-192 ROYAL SOC
Forbes RG (1998) Calculation of the electrical-surface (image-plane) position for aluminium, ULTRAMICROSCOPY 73 (1-4) pp. 31-35 ELSEVIER SCIENCE BV
Forbes RG (2012) Comment on 'Metallic nanowire-graphene hybrid nanostructures for highly flexible field emission devices', NANOTECHNOLOGY 23 (28) ARTN 288001 IOP PUBLISHING LTD
FORBES RG, LJEPOJEVIC NN (1989) RECENT PROGRESS IN LMIS THEORY, JOURNAL DE PHYSIQUE 50 (C8) pp. C83-C88 EDITIONS PHYSIQUE
Forbes RG (2003) More about the extraction of emission area from Fowler-Nordheim plots, TECHNICAL DIGEST OF THE 16TH INTERNATIONAL VACUUM MICROELECTRONICS CONFERENCE pp. 89-89 JAPAN SOC PROMOT SCI
Forbes RG (2001) Fundamental new results in the energetics and thermodynamics of charged metal surfaces, ULTRAMICROSCOPY 89 (1-3) pp. 1-5 ELSEVIER SCIENCE BV
Forbes RG (1972) A theory of field ion imaging: I - A quasi-classical site-current formula, Journal of Microscopy 96 pp. 57-61
FORBES RG (1980) DERIVATION OF SURFACE-ATOM POLARIZABILITY FROM FIELD-ION ENERGY DEFICITS, APPLIED PHYSICS LETTERS 36 (9) pp. 739-740 AMER INST PHYSICS
FORBES RG (1978) FIELD ADSORPTION - MONOPOLE-DIPOLE INTERACTION, SURFACE SCIENCE 78 (2) pp. L504-L507 ELSEVIER SCIENCE BV
Forbes RG (2002) Progress with the theory of cold cathode electron emission, pp. 41-43 Publishing House of the State Educational and Science Centre College, Saratov
Forbes R, Deane J, Fischer A, Mousa M (2015) Fowler-Nordheim Plot Analysis: a Progress Report, Jordan Journal of Physics 8 (3) pp. 125-147 Deanship of Research & Graduate Studies, Yarmouk University, Irbid, Jordan.
The commonest method of characterizing a cold field electron emitter is to measure its current-voltage characteristics, and the commonest method of analysing these characteristics is by means of a Fowler-Nordheim (FN) plot. This tutorial/review-type paper outlines a more systematic method of setting out the Fowler-Nordheim-type theory of cold field electron emission, and brings together and summarises the current state of work by the authors on developing the theory and methodology of FN plot analysis. This has turned out to be far more complicated than originally expected. Emphasis is placed in this paper on: (a) the interpretation of FN-plot slopes, which is currently both easier and of more experimental interest than the analysis of FN-plot intercepts; and (b) preliminary explorations into developing methodology for interpreting current-voltage characteristics when there is series resistance in the conduction path from the high-voltage generator to the emitter's emitting regions. This work reinforces our view that FN-plot analysis is best carried out on the raw measured current-voltage data, without pre-conversion into another data format, particularly if series resistance is present in the measuring circuit. Relevant formulae are given for extracting field-enhancement-factor values from such an analysis.
Kolosko A, Filippov S, Romanov P, Popov E, Forbes RG (2016) Real-time implementation of the "orthodoxy test" for conformity of current-voltage characteristics with classical field electron emission theory, JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B 34 (4) ARTN 04180 A V S AMER INST PHYSICS
An experimental apparatus and a LabView-based software suite were developed to conduct realtime research on field electron emission. The authors observed and analyzed the current?voltage characteristics of emitters based on carbon nanotube/polystyrene nanocomposites. A simple quantitative test was used to compare such characteristics with the classical field electron emission theory. Copyright 2016 American Vacuum Society
Forbes R (2017) The theoretical link between voltage loss, reduction in field enhancement factor, and Fowler-Nordheim-plot saturation, Applied Physics Letters 110 (13) 133109 pp. 133109-1 AIP Publishing
With a large-area field electron emitter, when an individual post-like emitter is sufficiently resistive, and current through it is sufficiently large, then voltage loss occurs along it. This letter provides a simple analytical and conceptual demonstration that this voltage loss is directly and inextricably linked to a reduction in the field enhancement factor (FEF) at the post apex. A formula relating apex-FEF reduction to this voltage loss was obtained in the paper by Minoux et al. [Nano Lett. 5, 2135 (2005)] by fitting to numerical results from a Laplace solver. This letter derives the same formula analytically, by using a ?floating sphere? model. The analytical proof brings out the underlying physics more clearly and shows that the effect is a general phenomenon, related to reduction in the magnitude of the surface charge in the most protruding parts of an emitter. Voltage-dependent FEF-reduction is one cause of ?saturation? in Fowler-Nordheim (FN) plots. Another is a voltage-divider effect, due to measurement-circuit resistance. An integrated theory of both effects is presented. Both together, or either by itself, can cause saturation. Experimentally, if saturation occurs but voltage loss is small (
Forbes RG (2017) Field electron emission theory, Young Researchers in Vacuum Micro/Nano Electronics (VMNE-YR) ISBN: 78-1-5090-4605-8 IEEE
This conference paper provides an overview of the
material presented in two field electron emission tutorial lectures
given at the 2016 Young Researchers' School in Vacuum Microand
NanoElectronics, held in Saint-Petersburg on October 5-6 2016.
This paper aims to indicate the scope and structure of the
tutorials, and also where some of the related published material
can be found.
Dall'Agnol Fernando F, de Assis Thiago A, Forbes Richard (2018) Physics-based derivation of a formula for the mutual depolarisation of two post-like field emitters, Journal of Physics: Condensed Matter 30 (37) 375703 IOP Publishing
Recent analyses of the apex field enhancement factor (FEF) for many forms of field emitter have revealed that the depolarization effect is more persistent with respect to the separation between the emitters than originally assumed. It has been shown that, at sufficiently large separations, the fractional reduction of the FEF decays with the inverse cube power of separation, rather than exponentially. The behavior of the fractional reduction of the FEF encompassing both the range of technological interest (c being the separation and h is the height of the emitters) and large separations () has not been predicted by the existing formulas in field emission literature, for post-like emitters of any shape. In this work, we use first principles to derive a simple two-parameter formula for fractional reduction that can be useful for experimentalists for modeling and interpreting the FEFs for small clusters of emitters or arrays at separations of interest. For the structures tested, the agreement between numerical and analytical data is ~1%.
Mayer Alexandre, Mousa Marwan S., Hagmann Mark J., Forbes Richard Numerical testing by a transfer-matrix technique of
Simmons' equation for the local current density in
metal-vacuum-metal junctions,
Jordan Journal of Physics Yarmouk University, Irbid, Jordan
We test the consistency with which Simmons' model can predict the local current density obtained for at metal-vacuum-metal junctions. The image potential energy
used in Simmons' original papers had a missing factor of 1=2. Besides this technical issue, Simmons' model relies on a mean-barrier approximation for electron transmission
through the potential-energy barrier between the metals. In order to test Simmons' expression for the local current density when the correct image potential
energy is included, we compare the results of this expression with those provided by a transfer-matrix technique. This technique is known to provide numerically exact solutions of Schrodinger's equation for this barrier model. We also consider the current
densities provided by a numerical integration of the transmission probability obtained with the WKB approximation and Simmons' mean-barrier approximation.
The comparison between these different models shows that Simmons' expression for the local current density actually provides results that are in good agreement with
those provided by the transfer-matrix technique, for a range of conditions of practical interest. We show that Simmons' model provides good results in the linear
and weld-emission regimes of current density versus voltage plots. It loses its applicability when the top of the potential-energy barrier drops below the Fermi level
of the emitting metal.