Sn掺杂对Ga2O3基日盲紫外探测器性能的影响研究

Effects of Sn doping on Ga2O3-based solar blind photodetectors

为了提高Ga2O3基日盲紫外探测器的性能,本文使用分子束外延方法对β-Ga2O3薄膜进行Sn掺杂,并制备成MSM型日盲紫外探测器。结果表明,Sn掺杂可以改变薄膜晶体结构,使氧化镓薄膜由单晶向多晶相转变。同时,Sn掺杂紫外探测器的光电流和响应度相比于未掺杂器件产生了较大的提升,在254nm、42μW/cm^2紫外光照下,Sn源温度900℃制备的薄膜探测器响应度为444.51A/W,远高于未掺杂器件。此外,器件的-3dB截止波长从252nm调整到274nm,表明Sn掺杂可以有效调控紫外响应的波长。Sn掺杂也会引入杂质能级,导致器件时间响应特性变差。

In order to improve the performance of Ga2O3-based photodetectors (PDs), Sn-doped gallium oxide thin films were prepared on sapphire substrates by molecular beam epitaxy system. The influence of Sn doping on both Ga2O3 crystal structure and photoelectric properties of metal-semiconductor-metal (MSM) PDs were investigated. X-ray diffraction shows that gallium oxide films change from single crystal to polycrystalline phase when increasing the growth temperature of SnO2. When 254 nm and 42 μW/cm2 light was used, the responsivity of Sn-doped Ga2O3 photodetectors reached 444.51 A/W. Compared with the undoped β-Ga2O3 PDs, the photocurrent and responsivity of Sn-doped PDs were almost increased by two orders of magnitude, suggesting the improvement on PD performance. Spectral response shows that the cut-off wavelength of Sn-doped PDs changes from 252 nm to 274 nm by increasing Sn dose, which reveals an efficient way toward the development of the UV PDs focus on longer wavelengths. However, Sn doping also introduces impurity levels, resulting in poor time response of the MSM PDs.