GaInNAs

When?

Monday 7 February 2011, 16:00

Where?

2 ATI 02

Open to:

Staff, Students

Speaker:

Judy Rorison, Dept of Electrical and Electronic Engineering, University of Bristol, Bristol, UK

GaInNAs  can be lattice matched to GaAs and emits light at useful optical communications wavelengths (1.3-1.55 micron) making it a potentially useful semiconductor material for optical communications. It has large conduction band offset making it more temperature independent than GaInAsP, the usual optical component material. It is a very interesting material as its behaviour is not that of a true alloy. It can be reasonably understood using a band anti-crossing model in which the localised N state interacts with the GaInAs conduction band. This model has proved very successful. When the concentration of N is increased additional N states (pair and cluster levels) arise and interact as well with the conduction band. This cannot be treated successfully within this model. Various models have been considered to treat this case and I will show a Green’s function approach which has been used successfully to derive a complex band structure and a density of states, required for optical and transport modelling. Recently Bi has been found to have similar effects on the GaInAs valence band offering the ability to tune the band gap and alter the Auger effects.

 In addition to the optical studies dilute nitride has applications as low noise photo-detectors, solar cells and as electronic devices exploiting negative differential resistance (NDR). The material properties and its applications will be reviewed.