Ultraviolet Photoresponse and Electroluminescence of Exfoliated Ga2O3 Flake on p-type GaN

초록

beta-phase Ga2O3 (beta-Ga2O3) is a promising candidate for deep ultraviolet (UV) solar-blind photodetector due to its large bandgap of 4.9 eV. A high crystal quality two-dimensional beta-Ga2O3 flake on p-type GaN (p-GaN) surface was formed using a facile mechanical exfoliation and transfer method, and the heterojunction photodiode consisting of an n-type beta-Ga2O3 flake on a p-type GaN substrate was fabricated. The device exhibited a distinctive rectifying current-voltage (I-V) characteristics with a rectification ratio of 4.0 x 105 at +/- 2 V. The photodetector responded to both 365 nm and 254 nm UV light irradiation with a photocurrent to dark current ratio of 5.64 x 105% for 365 nm and 3.38 x 105% for 254 nm UV. The rise and decay time constants for 365 nm and 254 nm deep UV exposure were obtained through dynamic time-dependent photocurrent measurements. In addition, electroluminescence of the p-type GaN/n-type Ga2O3 heterojunction diode was observed under high forward bias condition.

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