To produce a deep green (530 nm–570 nm) LED, the suitable indium (In) composition in the In_xGa_1-xN/GaN multi-quantum well (MQW) structure is crucial because a lower indium composition will shift the wavelength of emission towards the ultraviolet region. In this paper, we clarify the effects of an indium-rich layer to suppress such blue shifting, especially after the annealing process. According to characterizations by the uses of XRD and TEM, narrowing of the MQW layer was observed by the indium capping, while without the capping, the annealing results in a slight narrowing of MQW on the nearest layer to the p-type layer. By adding an indium capping layer, the blue shift of the photoluminescence was also suppressed and a slight red shift to keep green emission was observed. Such photoluminescence properties were consistent with the tiny change of the MQW as seen in the XRD and TEM characterizations.

中文翻译：

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铟预流对深绿色发光二极管的波长偏移和晶体结构的影响

为了生产深绿色（530 nm–570 nm）LED，In _x Ga _1-x中合适的铟（In）成分N / GaN多量子阱（MQW）结构至关重要，因为较低的铟成分会将发射波长移向紫外线区域。在本文中，我们阐明了富铟层抑制这种蓝移的作用，尤其是在退火过程之后。根据使用XRD和TEM的表征，通过铟封端观察到MQW层变窄，而没有封端，退火导致最接近p型层的MQW略微变窄。通过添加铟覆盖层，还抑制了光致发光的蓝移，并且观察到轻微的红移以保持绿色发射。如XRD和TEM表征所示，这种光致发光特性与MQW的微小变化一致。