InGaN/GaN多量子阱电池的垒层结构优化及其光学特性调控

InGaN基量子阱作为太阳电池器件的有源区时,垒层厚度设计以及实际生长对其光学特性的影响极为重要.采用金属有机化学气相沉积(MOVCD)技术,在蓝宝石衬底上外延生长了垒层厚度较厚的InGaN/GaN多量子阱,使用高分辨X射线衍射和变温光致发光谱研究了垒层厚度对InGaN多量子阱太阳电池结构的界面质量、量子限制效应及其光学特性的影响.较厚垒层的InGaN/GaN多量子阱的周期重复性和界面品质较好,这可能与垒层较薄时对量子阱的生长影响有关.同时,厚垒层InGaN/GaN多量子阱的光致发光光谱峰位随温度升高呈现更为明显的“S”形(红移-蓝移-红移)变化,表现出更强的局域化程度和更高的内量子效率.

Barrier Optimization and Optical Property Control of InGaN/GaN Multiple Quantum Wells

As an alternative for active region of solar cells, the barrier design and growth study of InGaN-based quantum well (QW) are of great concern. In this paper, InGaN-based multiple QWs with thick barrier layer were grown on c-plane sapphire substrates by metal-organic chemical vapor deposition (MOCVD). By using high-resolution x-ray diffraction (XRD) and temperature-dependent photoluminescence (PL) spectrum, it is investigated the effects of barrier thickness on interface quality, quantum confinement effect and optical characteristic of InGaN-based MQW solar cells. It demonstrates that thick-barrier InGaN-based MQWs exhibit good period repetitiveness and interface quality, which may overcome the bad influence of thin-barrier MQWs on the InGaN well layer. Meanwhile, its PL peak energy exhibits an obvious S-shaped temperature behavior (red-blue-red shift) with increasing temperature, which manifests a stronger localization extent with higher internal quantum efficiency.