基于三层模型的多孔硅发光谱双峰结构的研究

基于Litovchenko提出的多孔硅三层模型和在此基础上由Li等人提出的多孔硅三层发光模型,利用半导体异质结理论导出了多孔硅芯部与夹层中载流子浓度、非平衡载流子数目、扩散电流密度、夹层与芯部发光强度的比值等关系式.结果表明:当Egint＞Egcore时,在0.2 eV＜ΔEv+ΔEc＜0.26 eV范围内发光谱将出现双峰,并在ΔEv+ΔEc＞0区域发光峰位不断向高能移动,发生蓝移现象;当Egint＜Egcore时,尽管芯部由于量子限制效应仍将导致发光峰蓝移,但芯部的发光相对夹层的发光相当弱,这时多孔硅发光谱呈现单峰.此模型定量地解释了多孔硅发光峰的蓝移起源于多孔硅量子限制效应,而发光出现发光双峰和发光峰位钉扎是由夹层物质决定,说明了多孔硅的发光存在多种发光机制.

The study of double-peak structure in PS luminescence spectra

Based on the three-layer light-emitting model and the hetero-junction theory, the expressions of luminescence intensity ratio of interface layer to Si core were deduced. It was found that there was a double- peak structure in PS luminescence spectrum at the range of 0.2 eVE_ gcore , and the luminescen ce peak would move to high-energy when ΔE_v+ΔE_c>0. Because compa r ing with the interface layer luminescence intensity, the Si corn luminescence in tensity was too weak there would be a single peak when E_ gint< E_ gcore .The model interprets that the PS luminescence blue-shift origined from Quantum confinement Effect(OCE) while the double-peak and pinning phenomena were determined by the interface layer material.We can conclude that PS luminescence exists different mechanisms.