High figure-of-merit gallium oxide UV photodetector on silicon by MBE : a path toward monolithic integration
Mukhopadhyay, Partha and Hatipoglu, Isa and Sakthivel, Tamil Selvan and Hunter, Daniel A. and Gunasekar, Naresh Kumar and Edwards, Paul R. and Martin, Robert W. and Seal, Sudipta and Schoenfeld, Winston Vaughan (2021) High figure-of-merit gallium oxide UV photodetector on silicon by MBE : a path toward monolithic integration. Advanced Photonics Research, 2 (4). 2000067.
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Abstract
We demonstrate a high figure-of-merit UV–C solar-blind photodetectors fabricated from polycrystalline beta-gallium oxide (β-Ga2O3) grown on n-Si substrates by plasma assisted molecular beam epitaxy (PAMBE). We developed film growth sequences for nucleation of Ga2O3 on (100) and (111) oriented Si substrates, and systematically investigate the influence of crucial growth parameters, namely substrate temperature, oxygen flow rate and plasma power on the functional properties of the photodetectors. The photodetectors show ultra-high responsivity of 837 A/W and fast ON/OFF time below 4ms observed under 248 nm illumination at –5V. In addition, they display strong rectifying properties and sharp cut-off below 280 nm with average responsivities between 10-80 A/W, detectivity on the order of 1010 Jones, and rise/fall times between 4 to 500 ms at –5V. High photoconductive gain is shown to likely be due to the mid-bandgap donor/acceptor defect levels, including oxygen vacancies in the form of self-trapped holes. We demonstrate that these defect levels can be modified by controlling the growth conditions, thereby, allowing for tailoring of the photodetector characteristics for specific applications. Our methodology represents a cost-effective solution over homoepitaxial approaches, with characteristics that meet or exceed those reported previously, offering new possibilities for on-wafer integration with Si electronics.
ORCID iDs
Mukhopadhyay, Partha, Hatipoglu, Isa, Sakthivel, Tamil Selvan, Hunter, Daniel A., Gunasekar, Naresh Kumar


Item type: Article ID code: 74787 Dates: DateEvent7 April 2021Published8 December 2020Published Online30 November 2020Accepted14 November 2020SubmittedKeywords: UV-C photodetector, gallium oxide, molecular beam epitaxy, heterostructure, heterointegration, Physics, Physics and Astronomy(all) Subjects: Science > Physics Department: Faculty of Science > Physics Depositing user: Pure Administrator Date deposited: 03 Dec 2020 15:37 Last modified: 07 Apr 2021 11:33 URI: https://strathprints.strath.ac.uk/id/eprint/74787