垒掺In提高InGaN/GaN多量子阱发光特性

Enhanced luminescence of InGaN/GaN multiple quantum wells with indium doped GaN barriers

利用金属有机物化学气相淀积技术在蓝宝石衬底上生长InGaN/GaN多量子阱结构.对多量子阱垒层掺In和非掺In进行了比较研究,结果表明,垒掺In的样品界面质量变差,但明显增加了光致发光谱的峰值强度和积分强度,带边峰与黄光峰强度之比增大,降低了表面粗糙度.利用这两种结构制备了相应的发光二极管(LED)样品.通过电荧光测量可知,垒掺In的LED比非掺In的LED有较高的发光强度和相对均匀的波长,这主要是由于垒掺In后降低了阱与垒之间晶格失配的应力,从而降低了极化电场,提高了辐射复合效率.

InGaN/GaN multiple quantum wells have been grown by metal-organic chemical vapor deposition. InGaN/GaN mulitiple quantum well with and without indium doped GaN barriers were study. The results show the sample with In-doped GaN barrier had a poor interface, but the photoluminescence spectrum showed clearly increased peak intensity and integral intensity, enhanced IBL/IYL ratio and reduced surface roughness. Electroluminescence of light emitting diodes with In-doped GaN barrier had better relative intensity and wavelength uniformity. We presume that the introduction of indium is the dominant factor leading to the decrease of the lattice mismatch strain between well and barrier, decrease of piezoelectricity and improvement in radiative recombination efficiency.