GaAs1-xPx中混晶无序与Fe深中心的性质

对不同组分的掺FeⅢ-Ⅴ族混晶GaAs1-xPx,测量了Fe深受主中心空穴热发射的非指数恒温暗电容瞬态及DLTS谱。用混晶无序使Fe深能级展宽的模型理论拟合实验结果,得到Fe能级Gauss型展宽的半宽和中心能级的热发射率,并确定出基态空穴跃迁的中心能级的焓变与组分的关系:先是减少,而后增大,与由光电容方法得到的Gibbs自由能变量与组分x的关系明显不同。 进一步讨论表明,上述两种测量方法得到的Fe中心的激活能不同,可能反映Fe中心的键合状态和混晶无序诱导的品格弛豫的影响。

ALLOY DISORDER AND PROPERTIES OF Fe-CENTER IN GaAs1-xPx

Increasing attention has been recently paid to the deep centers in Ⅲ-Ⅴ semiconductor alloys since the main electronic properties of these materials vary continuously with their compositions and a large range of compositions can be selected for optimizing their applications such as for luminescence, laser and microelectronic devices. On the other hand, research on the dependence of deep center characteristics on alloy compositions can offer the possibilities to gain the important information about the centers from the point of view of defect physics.In this paper we report the measurement results for the nonexponential thermal transient capacitance and DLTS spectra in Fe-doped GaAsP alloy for large range of compositions.Samples used in this study were p+ n diode, n-type, GaAsP layers were grown on substrates of GaAs(for x<0.5) and GaP(for x>0.5) using MOVPE. The p+ layers were obtained by Zn diffusion, iron impurities were also diffused into samples and their concentrations were selected in the range of NFe/ND~0.05. The composition x of each samples studied was measured by microprobe analysis in a scanning electron microscope with uncertainty less than ±2%.