Semiconductor Ultraviolet Detectors

摘要

Materials and structures crucial to the development of semiconducting ultravioletdetectors were examined. The chemical beam epitaxy of GaN was compared to the growth of GaN using supersonic jet sources. The main characterization techniques employed were reflection high energy electron diffraction (RHEED) and desorption mass spectroscopy (DMS). It was found that a supersonic jet of molecular nitrogen seeded in molecular hydrogen would react at the surface to form GaN at incident energies exceeding 6.7 ev. The growth was compared to that from a supersonic jet of ammonia and a conventional ammonia leak. It was found that higher fluxes could be obtained using the ammonia leak. No differences in the growth were found using the ammonia jet. Using DMS it was found, however, that the jet assisted adsorption had different kinetics vs surface coverage than the ammonia adsorption. For the growth with ammonia, DMS and RHEED were used to establish a framework for the growth of GaN. This framework allows one to reproducible set growth conditions and predict rates. Finally Schottky barrier heights were measured and DX-like centers examined vs hydrostatic pressures.