GaN schottky diode with TiW electrodes on silicon substrate based on AlN/AlGaN buffer layer

We report the fabrication of GaN Schottky photodiodes (PDs) on Si(111) substrates coated with an AlN/AlGaN buffer multilayer. It was found that their dark current was much smaller than that of identical devices prepared on sapphire substrates. With an incident wavelength of 359 nm, the maximum responsivity of the n^--GaN Schottky photodetectors with TiW contact electrodes was 0.1544 A/W, corresponding to a quantum efficiency of 53.4%. For a given bandwidth of 1 kHz and bias of 5 V, the resultant noise equivalent power (NEP) of n^--GaN Schottky photodetectors with TiW electrodes was 1.033×10-12 W, corresponding to a detectivity (D) of 1.079×1012 cm-Hz^0.5 W^-1.