Wide Bandgap Ai/sub x/Ga/sub 1x/N Material System For Visible And Ultraviolet Optoelectronic Devices

AlxGa1-xN with it's tunable and direct bandgap is an important semiconductor system for visible and ultraviolet devices. The bandgap tunability from 200 nm at x = 1 to 365 nm at x= 0 combined with the tunable refractive index makes possible the fabrication of waveguide structures. Recently high quality single crustal films of AlN, GaN and AlGaN have been deposited over sapphire subs rates by several research groups using metalorganic chemical vapor deposition [1234]. N- and p- type doping [4,5] and high quality heterojunctions have also been reported[6]. These material quality improvements and control has resulted in several optoelectronic devices such as high responsivity UV detectors, Bragg reflectors, waveguides, transistors and visible LED's. We will briefly describe these recent advances and some current research directions.