【Domestic Papers】Solar-blind photodetectors prepared using semi-insulating Co:β-Ga₂O₃ single crystals that are stable over a wide temperature range

      The band-gap width of β-Ga₂O₃  is about 4.5~ 4.9eV, and the corresponding ultraviolet cutoff edge is in the Solar-blind band of 200~280 nm, so it can be used to make Solar-blind photodetectors without adjusting the band gap. Recently, the research team of Professor Jia Zhitai and Associate Professor Mu Wenxiang of Shandong University and the research team of Associate researcher Zhao Xiaolong of the University of Science and Technology of China cooperated to prepare a Solar-blind photodetector using Co doped β-Ga₂O₃ substrate (Co: β-Ga₂O₃). Compared with the devices prepared by using traditional Fe and Mg doped β-Ga₂O₃ substrate, The detector can maintain performance stability in a large temperature range from room temperature to 300 ° C. The relevant research results are entitled "Solar-blind photodetectors prepared using semi-insulating Co:β-Ga₂O₃ single crystals that are stable over a wide temperature range "was published in the Journal of Material Chemistry C.

Abstract

      Semi-insulated β-Ga₂O₃  is able to maintain a stable high resistivity over a wide temperature range, which is exactly the performance required for high-temperature environments, such as fire alarm, atmospheric monitoring, and space exploration. Compared with the traditional deep level acceptor (Fe, Mg, etc.), Co has a more suitable energy location, and its introduction into the band structure of β-Ga₂O₃  can inhibit the deterioration of the semi-insulation effect, maintain the stability of the resistivity, and make it have the possibility of application under harsh temperature conditions. In addition, Co:β-Ga₂O₃  has a high transmittance and a low free electron concentration. In this paper, the resistivity stability platform of Co:β-Ga₂O₃₃  at variable temperature was found for the first time, that is, the resistivity remained around 1011Ω ·cm at room temperature to 300 ℃, and its thermal activation energy fitting value was 2.1eV, which was closer to the center of band gap than Fe and Mg doping β-Ga₂O₃. Therefore, the dark current of the Co:β-Ga₂O₃  based photodetector can be effectively suppressed, and the photoresponse performance at room temperature to 260 ℃ has little change. This paper proposes and verifies the application prospect of Co:β-Ga₂O₃₃  with ultra-high resistivity stability and excellent semi-insulation effect in extreme environments, which provides more possibilities for the thermal design of β-Ga₂O₃  devices.

DOI: 10.1039/d3tc00906h