Electronic properties of nanocrystalline layers of wide-band-gap materials

The study presents an analysis of the properties of nanocrystalline wide-band-gap materials-diamond, BN, AlN, CN, GaN-as films produced by various plasma deposition techniques. The results of investigating their bulk as well as interface (i.e. layer-substrate) properties are shown and discussed. The influence of the nanocrystalline structure of the films on their electrophysical and optical characteristics, as well as on their phase composition and energy band diagrams configuration, was determined. Another phenomenon investigated was the influence of the plasma process parameters (like ion bombardment energy) on the structure of the layers, the dielectric strength of a layer, the substrate-interface region width, the density of states and of the electronic charge present in the bulk of the material and in the material substrate transition zone. The choice of substrate type was dependent on the requirements imposed by the research method employed or by the fact of its usability in such fields of application as optoelectronics, optics, mechanics and bioengineering. From the above point of view the usage of various technological processes (selective etching, doping and fabrication of metal contacts) was also analyzed. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.