High performance Schottky UV detectors (265–100 nm) using n-Al0.5Ga0.5N on AlN epitaxial layer

A high responsivity spectrum in the near ultraviolet (UV) and the vacuum UV (VUV) region was realized using Schottky UV detectors consisting of Al0.5Ga0.5N on an AlN epitaxial layer. The cut-off wavelength of AlGaN UV detectors was 4.7 eV (265 nm), a value that corresponds to the band gap of Al0.5Ga0.5N. The contrast of responsivity between the near UV and the visible was about 104. The GaN Schottky detector hads a high responsivity region in the near-UV from 3.4 to 5.0 eV (250–360 nm), whereas the AlGaN UV detector had a high responsivity in the UV–VUV region from 4.7 to 12.4 eV (100–265 nm). From these results, the fabricated AlGaN-based UV photodetectors can likely be used in detectors for the UV–VUV region. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)