Preparation of Sn-doped Ga₂O₃ thin films and their solar-blind photoelectric detection performance

Abstract

Abstract Sn doping is an effective way to improve the response rate of Ga 2 O 3 film based solar-blind detectors. In this paper, Sn-doped Ga 2 O 3 films were prepared on a sapphire substrate by radio frequency magnetron sputtering. The films were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and ultraviolet visible spectroscopy, and the effect of annealing atmosphere on the properties of films was studied. The Ga 2 O 3 films changed from amorphous to β -Ga 2 O 3 after annealing at 900 °C. The films were composed of micro crystalline particles with a diameter of about 5–20 nm. The β -Ga 2 O 3 had high transmittance for wavelengths above 300 nm, and obvious absorption for solar-blind signals at 200–280 nm. The metal semiconductor metal type solar-blind detectors were prepared. The detector based on Sn-doped β -Ga 2 O 3 thin film annealed in N 2 has the best response performance to 254 nm light. The photo-current is 10 μ A at 20 V, the dark-current is 5.76 pA, the photo dark current ratio is 1.7 × 10 6 , the response rate is 12.47 A/W, the external quantum efficiency is 6.09 × 10 3 %, the specific detection rate is 2.61 × 10 12 Jones, the response time and recovery time are 378 and 90 ms, respectively.