论文标题
β-GA2O3晶体中电荷载体重组的动力学
Kinetics of charge carrier recombination in beta-Ga2O3 crystals
论文作者
论文摘要
测量了阴极发光光谱，以确定β-GA2O3散装单晶中发光带和载体动力学的特征。发现CL发射是由3.40 eV达到峰值的宽UV发射的主导，该发射的温度随温度升高而表现出强烈的淬火。但是，其光谱形状和能量位置几乎保持不变。我们观察到随着激发密度的超级线性增加了CL强度。可以用Fe杂质中心的载体捕获和电荷转移来解释载体重组的这种动力学。该紫外线带的温度依赖性特性与自被捕的激活能量为48 +/- 10 MeV的自我捕获激子中弱结合的电子一致。除了自我捕获的激子发射外，蓝色发光（BL）带还与供体样缺陷有关，该缺陷在氢血浆退火后的浓度显着增加。负责BL（可能是氧空位）的点缺陷与表现出Huang-Rhys因子的晶格有很强的耦合。
Cathodoluminescence spectra were measured to determine the characteristics of luminescence bands and carrier dynamics in beta-Ga2O3 bulk single crystals. The CL emission was found to be dominated by a broad UV emission peaked at 3.40 eV, which exhibits strong quenching with increasing temperature; however, its spectral shape and energy position remain virtually unchanged. We observed a super-linear increase of CL intensity with excitation density; this kinetics of carrier recombination can be explained in terms of carrier trapping and charge transfer at Fe impurity centres. The temperature-dependent properties of this UV band are consistent with weakly bound electrons in self-trapped excitons with an activation energy of 48 +/- 10 meV. In addition to the self-trapped exciton emission, a blue luminescence (BL) band is shown to be related to a donor-like defect, which increases significantly in concentration after hydrogen plasma annealing. The point defect responsible for the BL, likely an oxygen vacancy, is strongly coupled to the lattice exhibiting a Huang-Rhys factor of ~ 7.3.
