Materials with physical dimensions reduced to the nanoscale (less than 100 nm) can exhibit markedly different properties compared to those on larger length-scales.
This is mainly a result of the massively increased fraction of atoms that are at the surface of the material or the confinement of charge carriers on length scales similar to their quantum mechanical wavelength.
Much of the interest in nanotechnology stems from these unique quantum and surface phenomena that matter exhibits at the nanoscale. As the majority of the atoms in these nanostructures are a short distance from the surface, the optical and electrical properties of these systems can be strongly modified by changes in their environment, allowing a host of applications particularly in sensing.
In recent years the techniques for growing and fabricating nanoscale materials have matured significantly, to the point where researchers are able to tailor their properties toward particular applications, allowing the production of truly functional nanomaterials, which utilise these properties and allow the fabrication of range of new and exciting technologies. In the NEC group we are investigating many different functional nanomaterials, such as metal nanoparticles, metal oxide nanowires and carbon nanotubes for a range of applications including physical, chemical and environmental sensors, energy scavenging materials, low-cost transparent conductors and optoelectronic devices.
M. J. Beliatis, N. A. Martin, E. J. Leming, S. R. P. Silva, and S. J. Henley, “Laser Ablation Direct Writing of Metal Nanoparticles for Hydrogen and Humidity Sensors”, Langmuir, 27, 1241 (2011)
Researchers in the NEC group have recently demonstrated a laser writing technique to produce miniature vapour nanosensors, based around metal nanoparticles, on low cost substrates. The processing conditions are in ambient air and the devices, including all electrodes, were fabricated in one step. Sensors based on Palladium metal nanoparticles where fabricated and tested and shown to be able to detect hydrogen, and gold nanoparticle sensors were fabricated to detect relative humidity.