Effects of high substrate temperature during pulsed laser deposition on the quality of aluminum-doped gallium oxide and its photodetector characteristics

We report on the effects of substrate temperature (600–800 °C) on metal–semiconductor–metal photodetectors (PDs) fabricated with aluminum-doped gallium oxide (AGO) films by pulsed laser deposition. The crystal quality of the AGO films was improved by increasing the substrate temperature. Because of the AGO(400) appearance, the d-spacing of AGO decreased, whereas the strain of this plane increased. This could be explained by the formation of the AGO(400) plane in the films, generating a compressive strain in the AGO plane. The AGO PDs showed a maximum absorption at a wavelength of 240 nm, and the enhanced crystal quality would benefit the device performance.