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

Sn doping is an effective way to improve the response rate of Ga2O3 film based solar-blind detectors.In this paper,Sn-doped Ga2O3 films were prepared on a sapphire substrate by radio frequency magnetron sputtering.The films were charac-terized by X-ray diffraction,scanning electron microscopy,X-ray photoelectron spectroscopy and ultraviolet visible spec-troscopy,and the effect of annealing atmosphere on the properties of films was studied.The Ga2O3 films changed from amor-phous to β-Ga2O3 after annealing at 900 ℃.The films were composed of micro crystalline particles with a diameter of about 5–20 nm.The β-Ga2O3 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-Ga2O3 thin film annealed in N2 has the best response performance to 254 nm light.The photo-current is 10 μA at 20 V,the dark-current is 5.76 pA,the photo dark current ratio is 1.7×106,the response rate is 12.47 A/W,the external quantum efficiency is 6.09×103％,the spe-cific detection rate is 2.61×1012 Jones,the response time and recovery time are 378 and 90 ms,respectively.