Improving the production of high-performance solar-blind β-Ga2O3 photodetectors by controlling the growth pressure

In this work, β-Ga2O3 films are obtained by the RF magnetron sputtering method. Effects of the growth pressure on properties of the deposited β-Ga2O3 films and the corresponding solar-blind metal–semiconductor–metal photodetectors are investigated systematically. It is shown that when the deposition pressure increases, the full width at half maximum of β-Ga2O3 $$ \left( {\bar{2}01} \right) $$ X-ray diffraction peaks decreases firstly and then increase. The peak intensities increase firstly, reach a maximum at 25 mTorr and then decrease with increasing pressure. The similar variation tendency is also reflected on the bandgap, oxygen vacancy and roughness of β-Ga2O3 films. It is supposed that all these properties depend on two factors: atoms diffusion ability and the defects with growth pressure. By controlling the growth pressure, the fabricated interdigitated solar-blind photodetectors exhibit excellent characteristics, including a large spectral responsivity (303 A/W), a low dark current (10pA at 20 V), a large photo-to-dark current ratio (> 105), a high external quantum efficiency (over 1 × 105%) and a fast response speed (rise time: 0.52 s and fall time: 0.12 s).