Solarblind and visibleblind photodetectors based on the AlGaN

AlGaN material system with the maximum band gap energy of 6.1 eV allows to manufacture ultraviolet (UV) optoelectronic devices working within a wide UV-A, B, C spectral range with a minimum wavelength of 210 nm. However, fabrication of the low-resistance ohmic contact to AlxGa1-xN with a high Al content (x > 0.5) is a difficult and actual task. The best results on the AlGaN-based Schottky-type photodetectors were obtained by using Au (15nm) and Ti/Al (15/35nm) as barrier and ohmic contacts, respectively. The sequential short-wavelength shift of the photo-response curves toward deep UV (solar-blind) range with the minimum achieved cut-off wavelength less than 250 nm was observed for the structures with a Al-content as high as x = 0.6.