Investigation carrier transition of β-Ga2O3 based solar-blind photodetectors working over 300 °C

In this paper, we demonstrate β-Ga2O3 solar-blind photodetectors working over 300 °C and investigate the carrier transition mechanism. The (−201) β-Ga2O3 films were grown on sapphire substrates using the carbothermic reduction method and further fabricated into a metal–semiconductor–metal solar-blind photodetector. The solar-blind photodetectors exhibited a low dark current of approximate 10 pA and a high photo-to-dark current ratio (PDCR) of approximately 4419 at a high temperature of 300 °C, thanks to the Schottky barrier that impedes thermally excited carriers from overcoming the barrier to enter the semiconductor conduction. The multiple cycles of the transient response curve of β-Ga2O3 solar-blind photodetectors demonstrated its repeatability and reversibility at high temperatures. Above 300 °C, the dark current displays a sharp increase while the PDCR exhibits a dramatic descent of several orders of magnitude. The reason could be explained by the carrier transition mechanism shifted to the thermionic field emission model at high temperature by analyzing the fitting curve of dark current over 400 °C causing a sharp increase in dark current and degeneration of device performance.