Solar-blind photodetectors fabricated on β-Ga2O3 films deposited on 6° off-angled sapphire substrates

In this paper, the β-Ga2O3 films were deposited on 6° off-angled (towards <11–20> direction) (0001) sapphire substrates by MOCVD, and the MSM structure solar-blind photodetectors were fabricated. The effects of growth temperature on the surface morphology, elemental composition, crystalline quality and optical properties of β-Ga2O3 thin films were investigated. As the substrate temperature increased from 650 to 850 °C, the surface RMS roughness of the film gradually increased, and the bandgap was 4.71, 4.73 and 4.76 eV, respectively. In addition, the photodetector fabricated on β-Ga2O3 film at 850 °C exhibited a large photocurrent (Iphoto) of 0.59 mA, a high responsivity (R) of 1.26 A/W, a high photo-to-dark current ratio (PDCR) of 9.3 × 104, a detectivity (D*) of 2.5 × 1012 Jones, and a fast response recovery time of 0.38 s.