Development of high-performance III-Nitride-based semiconductor devices

In the past decade, research work in AlGaInN wide band gap semiconductors has continuously intensified, mainly because of their exceptional expected material properties which make them the ideal materials for numerous devices, including solar blind ultraviolet photodetectors. In this paper, the growth and characterization of AlGaInN thin films on sapphire and silicon substrates by metalorganic chemical vapor deposition is presented. The fabrication and testing results of GaN and Al_xGa_1-xN based ultraviolet photodetectors are discussed, including high speed low noise GaN based Schottky metal-semiconductor-metal photodetectors with high ratio of rejection of visible light to UV light, high visible blindness GaN p-i-n photodiodes, Al_xGa_1-xN photoconductors in the entire Al compositional range, and the first Al_xGa_1-xN p-i-n photodiodes (0 ≤ x ≤ 0.15) ever reported. Finally, in an on-going effort to improve the quality of AlGaInN materials, the LEO growth and characterization of low defect density GaN films on both (00.1) sapphire and (111) silicon substrates is described.