Solar blind Schottky photodiode based on an MOCVD-grown homoepitaxial β-Ga2O3 thin film

摘要

We report on a high performance Ptsup?/supGasub2/subOsub3/subsup+/supGasub2/subOsub3/sub solar blind Schottky photodiode that has been grown by metalorganic chemical vapor deposition. The active area of the photodiode was fabricated using ～30 ? thick semi-transparent Pt that has up to 90% transparency to UV radiation with wavelengths 260 nm. The fabricated photodiode exhibited Schottky characteristics with a turn-on voltage of ～1 V and a rectification ratio of ～10sup8/sup at ±2 V and showed deep UV solar blind detection at 0 V. The Schottky photodiode exhibited good device characteristics such as an ideality factor of 1.23 and a breakdown voltage of ～110 V. The spectral response showed a maximum absolute responsivity of 0.16 A/W at 222 nm at zero bias corresponding to an external quantum efficiency of ～87.5%. The cutoff wavelength and the out of band rejection ratio of the devices were ～260 nm and ～10sup4/sup, respectively, showing a true solar blind operation with an excellent selectivity. The time response is in the millisecond range and has no long-time decay component which is common in photoconductive wide bandgap devices.