Dual-Schottky-junctions coupling device based on ultra-long β-Ga₂O₃ single-crystal nanobelt and its photoelectric properties

Abstract

High quality β-Ga2O3 single crystal nanobelts with length of 2−3 mm and width from tens of microns to 132 μm were synthesized by carbothermal reduction method. Based on the grown nanobelt with the length of 600 μm, the dual-Schottky-junctions coupling device (DSCD) was fabricated. Due to the electrically floating Ga2O3 nanobelt region coupling with the double Schottky-junctions, the current I S2 increases firstly and rapidly reaches into saturation as increase the voltage V S2. The saturation current is about 10 pA, which is two orders of magnitude lower than that of a single Schottky-junction. In the case of solar-blind ultraviolet (UV) light irradiation, the photogenerated electrons further aggravate the coupling physical mechanism in device. I S2 increases as the intensity of UV light increases. Under the UV light of 1820 μW/cm2, I S2 quickly enters the saturation state. At V S2 = 10 V, photo-to-dark current ratio (PDCR) of the device reaches more than 104, the external quantum efficiency (EQE) is 1.6 × 103%, and the detectivity (D*) is 7.5 × 1012 Jones. In addition, the device has a very short rise and decay times of 25−54 ms under different positive and negative bias. DSCD shows unique electrical and optical control characteristics, which will open a new way for the application of nanobelt-based devices.