The low efficiency of green light-emitting diodes (LEDs), a phenomenon known as the green gap, is a key obstacle hindering the application of LEDs as next-generation light sources to pioneer a plethora of new applications in the optical, medical, and communication sectors. Based on a microscopic photoluminescence analysis of green GaN-based multiple quantum wells, we find that In-enriched emission clusters on the submicrometer scale, previously thought to be efficient luminescent centers, do not emit light effectively. Such emission clusters can localize an excessively large amount of carriers, leading to the subsequent occurrence of vigorous nonradiative recombination processes. We also observe that the effective volume of the LED active region is significantly reduced, possibly because the generation of these In-enriched clusters via metastable phase separation significantly degrades the surrounding crystal quality. The microscopic analysis of luminescent clusters gives insight into the low efficiency of green LEDs, which may guide future directions for the development of LEDs.

中文翻译：

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在绿色发光二极管中的低效率的微观观察

绿色发光二极管（LED）的低效率（一种称为绿色间隙的现象）是阻碍将LED用作下一代光源以在光学，医疗和照明领域开拓众多新应用的主要障碍。通讯部门。基于绿色的基于GaN的多量子阱的显微光致发光分析，我们发现亚微米级的In-富集发射簇以前被认为是有效的发光中心，不能有效发光。这样的发射簇可以使过多的载流子局部化，从而导致随后发生剧烈的非辐射重组过程。我们还观察到，LED有源区的有效体积显着减小，可能是因为通过亚稳相分离产生的这些富In团簇会大大降低周围晶体的质量。发光团簇的微观分析可洞察绿色LED的低效率，这可为LED的发展提供指导。