氧化镓薄膜的制备及其日盲紫外探测性能研究

采用射频磁控溅射方法在蓝宝石单晶衬底上沉积氧化镓(Ga2O3)薄膜,并通过光刻剥离工艺(Lift-off)制备了金属-半导体-金属结构的Ga2O3日盲紫外探测器。对不同温度下沉积的Ga2O3薄膜分析表明,在800℃下获得的薄膜结晶质量最好,薄膜的导电性则随着沉积温度的上升先增大后减小。在800℃制备的β-Ga2O3薄膜的可见光透光率大于90%,光学吸收边在255 nm附近。在10 V偏压下,探测器的暗电流约为1n A,光电流达800 n A,对紫外光响应迅速。器件的响应度达到0.3 A/W,260 nm波长处的响应度是290 nm波长对应响应度的40倍,可实现日盲紫外波段的探测。

Preparation and Ultraviolet Detection Performance of Ga2 O3 Thin Films

Gallium oxide(Ga₂O₃) thin films were depsited by radio frequency magnetron sputtering on sapphire(0001) substrates with a range of substrate temperatures from 500 to 1 000 ℃. The norphological characteristics, optical bandgaps, electrical properties and photoresponsivity of the grown thin films were researched.With the increasing of the growth temperature, the crystallinity and conductivity of the films increase at first and then decrease slightly. Ultraviolet-visible spectra indicate that the transmittance of β-Ga₂O₃ film depsited on 800 ℃ is over than 90%, and it's absorption edge is located at about 255 nm, meaning that the optical bandgap was about 4.8 eV. The metal-semiconductor-metal photodetector based on β-Ga₂O₃ film shows dark current of ~1 nA and photocurrent of ~800 nA under 254 nm light illumination at 10 bias voltage. The maximum responsivity of the photodetector is 0.3 A/W at 260 nm, 40 times as much as the responsivity at 290 nm.