Solar-blind Schottky photodiodes based on AlGaN:Si/AlN, grown by plasma-activated molecular beam epitaxy

The article describes solar-blind Schottky photodiodes based on AlGaN heterostructures grown by plasma-activated molecular beam epitaxy on c-sapphire substrates with various AlN buffer layers. X-ray diffraction analysis and chemical surface etching were used to estimate density of the threading dislocation that affect leakage currents and spectral sensitivity of photodiodes. Optimization of the photodiodes design and the Ti/Al/Ti/Au contact layer made it possible to achieve a photosensitivity of 51 mA/W in the solar-blind range ($\lambda$ = 290 nm) in the photovoltaic mode.