MBE-grown AlGaN/GaN heterostructures for UV photodetectors

The MBE synthesis of AlGaN/GaN semiconductor heterostructures intended for UV photodetectors is considered. A technique for growing AlGaN layers and multilayered heterostructures is developed. It includes the nitridization of the sapphire substrate surface, the formation of a seed layer, and the growth of a buffer layer and undoped and doped AlGaN layers of different composition. The influence of growth conditions on the surface morphology, density of threading dislocations and other structural defects, and electrophysical and optical properties of individual AlGaN layers and respective heterostructures for UV photodetectors is investigated. The mathematical simulation of $p$–$i$–$n$ photodiodes is made, and a process route for fabrication of AlGaN heterostructures is developed. Test AlGaN $p$–$i$–$n$ photodiodes are prepared, and their performance is investigated.