Effects of growth cycle number and annealing temperature on Ga2O3-on-quartz solar-blind photodetectors

In this study, Ga2O3 thin films were deposited on quartz glass substrates by atomic layer deposition technique followed by post annealing process. The influence of growth cycle number and post annealing temperature on both their material characteristics and UV photoelectric properties was studied. The crystal structure can be improved and the photo-current increases in a geometric progression with the increase of the number of cycles. In addition, the effect of annealing temperature on Ga2O3-based solar-blind photodetectors have been studied. The annealing temperature was set to 400 °C, 500 °C, 600 °C, 700 °C, 800 °C and 900 °C, respectively. The surface morphology deteriorates seriously when the annealing temperature is above 600 °C, leading to the poor photoresponsivity (<1 A/W) of Ga2O3 PDs. The amorphous Ga2O3 film annealed at 400 °C in N2/Air mixture atmosphere shows the maximum disorder and minimum optical band gap, which results in the lower UV transmittance and higher photoresponsivity of 1166.6 A/W under 254 nm illumination. The results show that the Ga2O3 photoelectric detectors based on quartz substrate not only reduces the cost of solar-blind photodetectors cost, but also has excellent photoelectric performance.