AlGaN双势垒结构对高In组分InGaN/GaN MQWs太阳能电池材料晶体质量和发光性能的影响

本文利用金属有机化合物化学气相沉积(MOCVD)技术在(001)面图形化蓝宝石衬底(PSS)上生长了一种含有AlGaN-InGaN/GaN MQWs (multiple quantum wells)-AlGaN双势垒结构的高In组分太阳能电池外延材料。高分辨率X射线衍射(HRXRD)和光致发光(PL)谱分析表明,与含有AlGaN电子阻挡层的低In组分的量子阱结构太阳能电池外延材料相比,该结构材料具有较小的半峰全宽(FWHM),计算表明:此结构材料的位错密度降低了一个数量级,达到10⁷ cm^-2;同时,有源区中的应变弛豫降低了51%;此外,此结构材料的发光强度增强了35%。研究结果表明含有AlGaN双势垒结构的外延材料可以减小有源区的位错密度,降低非辐射复合中心的数目,增大有源区有效光生载流子的数目,为制备高质量太阳能电池提供实验依据。

Influence of AlGaN Double Barrier Structure on Crystal Quality and Luminescent Properties of InGaN/GaN MQWs Solar Cell Materials Containing High Indium Components

In this paper, a double-barrier structure AlGaN-InGaN/GaN MQWs-AlGaN solar cell materials containing high indium components was grown on (001)-oriented patterned sapphire substrate (PSS) by metal organic chemical vapor deposition (MOCVD) technology. Compared with the MQWs solar cell material containing AlGaN electron barrier structure with low indium, it is found that the material of this structure has a smaller full width at half maximum (FWHM) by high-resolution X-ray diffraction (HRXRD) and photoluminescence (PL) spectroscopy analysis, and the dislocation density of this structural material is also reduced by an order of magnitude to 10⁷ cm^-2 by the dislocation density formula; at the same time, the strain relaxation in the active region decreases by 51%. In addition, luminous intensity of this structural material is enhanced by 35%. The results show that the epitaxial material containing AlGaN double barrier structure can reduce the dislocation density in the active region, decrease the number of non-radiative recombination centers, and increase the number of effective photo-generated carriers in the active region, which provides experimental basis for the preparation of high efficiency solar cells.