Preparation of Ga2O3 thin film solar-blind photodetectors based on mixed-phase structure by pulsed laser deposition**Project supported by the National Natural Science Foundation of China (Grant Nos. 51872187, 51302174, 11774241, and 61704111), the National Key Research and Development Program of China (Grant No. 2017YFB0400304), the Natural Science Foundation of Guangdong Province, China (Grant Nos. 2016A030313060 and 2017A030310524), the Project of Department

Abstract

Gallium oxide (Ga2O3) thin films were deposited on a-Al2O3 ( substrates by pulsed laser deposition (PLD) with different oxygen pressures at 650 °C. By reducing the oxygen pressure, mixed-phase Ga2O3 films with α and β phases can be obtained, and on the basis of this, mixed-phase Ga2O3 thin film solar-blind photodetectors (SBPDs) were prepared. Comparing the responsivities of the mixed-phase Ga2O3 SBPDs and the single β-Ga2O3 SBPDs at a bias voltage of 25 V, it is found that the former has a maximum responsivity of approximately 12 A/W, which is approximately two orders of magnitude larger than that of the latter. This result shows that the mixed-phase structure of Ga2O3 thin films can be used to prepare high-responsivity SBPDs. Moreover, the cause of this phenomenon was investigated, which will provide a feasible way to improve the responsivity of Ga2O3 thin film SBPDs.