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 Al 0.5 Ga 0.5 N 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 Al 0.5 Ga 0.5 N. The contrast of responsivity between the near UV and the visible was about 104. The GaN Schottky detector had 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.