Deep-Ultraviolet Photodetectors Based on Epitaxial ZnGa2O4 Thin Films

Si Han Tsai, Sarbani Basu, Chiung Yi Huang, Liang Ching Hsu, Yan Gu Lin, Ray-Hua Horng*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

A single-crystalline ZnGa2O4 epilayer was successfully grown on c-plane (0001) sapphire substrate by metal-organic chemical vapor deposition. This epilayer was used as a ternary oxide semiconductor for application in high-performance metal–semiconductor–metal photoconductive deep-ultraviolet (DUV) photodetectors (PDs). At a bias of 5 V, the annealed ZnGa2O4 PDs showed better performance with a considerably low dark current of 1 pA, a responsivity of 86.3 A/W, cut-off wavelength of 280 nm, and a high DUV-to-visible discrimination ratio of approximately 107 upon exposure to 230 nm DUV illumination than that of as-grown ZnGa2O4 PDs. The as-grown PDs presented a dark current of 0.5 mA, a responsivity of 2782 A/W at 230 nm, and a photo-to-dark current contrast ratio of approximately one order. The rise time of annealed PDs was 0.5 s, and the relatively quick decay time was 0.7 s. The present results demonstrate that annealing process can reduce the oxygen vacancy defects and be potentially applied in ZnGa2O4 film-based DUV PD devices, which have been rarely reported in previous studies.

Original languageEnglish
Article number14056
JournalScientific reports
Volume8
Issue number1
DOIs
StatePublished - 1 Dec 2018

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