【Domestic Papers】The research team of Xi'an University of Posts and Telecommunications is interested in Dual Schottky junctions coupling device based on ultra long β-Ga₂O₃ single crystal nanobelt and its photoelectric properties

      Researchers from the Xi’an University of Posts and Telecommunications have published a dissertation titled "Dual-Schottky-junctions coupling device based on ultra-long β-Ga₂O₃ single-crystal nanobelt and its photoelectric properties " in Journal of Semiconductors.

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.

Fig. 1. (a) SEM diagram of synthesized ultra-large nanobelts which are about 2−3 mm in length. (b) the enlargement of the yellow dotted box of Fig. (a). Maximum width of these nanobelts is up to 132 μm. (c) XRD pattern of nanobelt. (d) Electron diffraction patterns of selected regions. (e) Low-resolution TEM image of nanobelt. (f) High resolution TEM image of nanobelt.

Fig. 2. (a) Schematic diagram of device structure. (b) Image of the actual fabricated device. (c) Energy band of Schottky junction under positive bias. W is the width of depletion layer. (d) I−V curves of Schottky junctions of S₁−O₁ and S₂−O₂ , respectively.

Paper Link：http://www.jos.ac.cn/en/article/id/87d43897-9269-4cae-855b-d565d7a41e3a