高掺杂半导体的带尾结构及其对载流子瞬态分布的影响

本文从理论上分析了稳态和瞬态情况半导体自发发射光谱峰值与载流子在能带中的分布极大值之间的关系;载流子分布极大值位于带尾中的条件;载流子分布极大值在带尾中随注入水平变化的快慢与带尾形状以及载流子是否达到准平衡分布的关系。建立了从稳态和瞬态发射光谱的峰值移动规律定量地确定带尾态密度分布的新方法,并得出了在掺双性硅的GaAs,自发发光的瞬态过程中不存在准费米能级的重要结论。实验上系统地测量了掺有不同杂质、不同掺杂浓度和补偿度的GaAs同质结和异质结样品在不同注入水平下在300K和77K的稳态和瞬态时间分辨光谱。实验结果与理论预期相当符合,并据此探讨了带尾对发光瞬态响应时间的影响。

BANDTAIL-STRUCTURE IN HEAVILY DOPED SENICONDUCTOR (GaAs) AND TS INFLUENCE ON THE TRANSIENT DISTRIBUTION OF INJECTED CARRIERS

The correlation between the Peak of spontaneous spectra and the maximum of the injected carrier distribution in the energy band, the condition of the carrier distribution-maximum situated in the bandtail; the dependence of the carrier-distribution-maximum shifting-rate with injection level on the shape of the bandtail, and on whether or not the quasi-equilibrium distribution has been reached, have been analysed theoretically both under steady and transient cases.A new method for quantitatively determining the density-of-states distribution of the tail from the steady and transient emission spectra peak shifting is proposed. An important conclusion is that quansi-Fermi level do not exist during transient spontaneous emissions from GaAs doped with amphoteric silicon. Steady and transient time-resolved spectra from GaAs homojunction and heterojunc-tion samples doped with various dopants of different concentrations and different degrees of compensation, under various injection levels at 300 and 77K, are systematically measured. The experimental results agree well with the theoretical predictions, and on this qasis, the effect of bandtailing on the transient response time of spontaneous emission Is discussed.