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

In this paper, the beta-Ga2O3 films were deposited on 6 degrees 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 beta-Ga2O3 thin films were investigated. As the substrate temperature increased from 650 to 850 degrees 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 beta-Ga2O3 film at 850 degrees 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 x 10(4), a detectivity (D*) of 2.5 x 10(12) Jones, and a fast response recovery time of 0.38 s.