Visible-blind and solar-blind ultraviolet photodiodes based on (InxGa1-x)2O3

UV and deep-UV selective photodiodes from visible-blind to solar-blind were realized based on a Si-doped (InxGa1-x)(2)O-3 thin film with a monotonic lateral variation of 0.0035 < x < 0.83. Such layer was deposited by employing a continuous composition spread approach relying on the ablation of a single segmented target in pulsed-laser deposition. The photo response signal is provided from a metal-semiconductor-metal structure upon backside illumination. The absorption onset was tuned from 4.83 to 3.22 eV for increasing x. Higher responsivities were observed for photodiodes fabricated from indium-rich part of the sample, for which an internal gain mechanism could be identified. (C) 2016 AIP Publishing LLC.