Cool Heterojunction Metal Semiconductor Metal Photodetect

Metal Semiconductor Metal (MSM) photodetectors are used in a wide range of commercial and military applications such as phased array radars, photonic gates for MIMIC circuits, analog circuits for imaging with neutral networks, optical detectors for communication links and optical ports for computer optical interconnects. The performance of these MSM detectors can be greatly enhanced through the use of GaAs materials grown at low temperatures. The low temperature material exhibit short carrier lifetimes due to trapping by defects. This results in reduced response times and, resulting, higher frequency response as already reported in the literature. This work proposed here involves the novel addition of a GaAs/AlGaAs heterojunction which yields carrier conduction in a two dimensional electron gas which greatly improves the electron mobility. The enhanced mobility allows the detector to respond to higher frequency modulation. The epitaxial wafers will be grown using the molecular beam epitaxy technique to allow excellent control of the material parameters as required for high performance operation. The ability to modulate MSM photodetectors at higher speed to allow greater amounts of information to be transmitted. The use of the AlGaAs/GaAs heterojunction should greatly improve the frequency response of the MSM photodetector.