Cubic Nitride Semiconductor Heterostructures and Their Application to Optical and Electronic Devices

点击翻译按钮获取中文摘要

This research project has demonstrated the feasibility of practical device application of cubic phase nitride semiconductors and heterostructures. As for the GaN thin films on GaAs substrates, high quality cubic GaN epitaxial films that contains hexagonal GaN less than 1 % have been attained by improvement of metal-organic vapor phase epitaxy (MOVPE) growth technique including adoption of GaN intermediate layers and arsenic overpressures in the growth process. High quality cubic GaN films showed a highly luminescent optical property without deep-level luminescence coming from crystal defects. Microscopic structural analyses revealed the details of hexagonal phase generation in cubic GaN films. Si doping has been successful to realize high-conductivity n-type electrical conduction. Selective-area growth of cubic GaN films using fine lithography stripe mask patterns has given a superior quality cubic GaN when the stripe orientation is along the proper crystal orientation. Detailed characterization of cubic GaN/GaAs heterointerface using photoconductivity and electroreflectance clarified the existence of parallel conduction path due to the specific band-line up of the heterostructure. Molecular-beam epitaxy (MBE) using rf-plasma nitrogen source gave cubic GaN and InN films on GaAs with comparable quality with MOVPE-grown films. These achievements shows a possibility of practical applications of cubic nitride semiconductors.