Ar等离子体处理对GaAs纳米线发光特性的影响

Effects of Ar Plasma Treatment on Photoluminescence Properties of GaAs Nanowires

采用Ar等离子体处理GaAs纳米线,通过光致发光测试研究了等离子体偏压功率对GaAs纳米线发光性能的影响。在不同测试温度和不同激发功率密度下,研究了发光光谱各个发光峰的来源和机制。研究结果表明:随着功率增加,GaAs自由激子发光逐渐消失,束缚激子发光强度先减小后增大;当功率增加到200 W时,出现施主-受主对(DAP)发光。通过对比不同样品在283℃下的发光光谱,得到了等离子体处理过程中GaAs纳米线的结构变化:当处理功率较小时,Ar等离子体在消除表面态的同时将空位缺陷引入GaAs中;当处理功率较大时,GaAs的晶体结构遭到破坏,形成施主类型的缺陷,出现DAP发光。

GaAs nanowires are treated with Ar plasma, and the effects of the bias power of plasma on the photoluminescence properties of the GaAs nanowires are studied by the photoluminescence test. The source and mechanism of each photoluminescence peak in photoluminescence spectra are studied at different temperatures and different excitation powers. The experimental results show that the free exciton emission of GaAs gradually disappears and the bound exciton emission decreases first and then increases with the increase of the power. When the power increases to 200 W, the donor-acceptor pair(DAP) emission appears. Comparing the photoluminescence spectra of different samples at 283 K, we obtain the structural changes of GaAs nanowires during plasma treatment. When the processing power is low, the Ar plasma eliminates the surface state and introduces a vacancy defect in GaAs;when the processing power is high, the crystal structure of GaAs is destroyed, and the DAP emission appears.