Effects of an InGaN prelayer on the properties of InGaN/GaN quantum well structures
Effects of an InGaN prelayer on the properties of InGaN/GaN quantum well structures
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InGaN预层对InGaN/GaN量子阱结构性能的影响
DOI：
10.1002/pssc.201300451
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
Davies M
中科院分区：
文献类型：
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作者：
Davies M
在本文中，我们报告的影响，包括InGaN/GaN多量子阱（MQW）结构中的InGaN预层。研究了两个等效的10周期In 0.16Ga 0.84N MQW结构，一个具有24 nm厚的In 0.05Ga 0.95N预层，一个没有。X射线衍射测量显示在包含预层的结构中没有应变松弛的证据，而AFM显示“V”缺陷的平均直径增加了15%。温度依赖的光致发光（PL）表明，MQW结构，与预层，表现出更高的室温内量子效率比参考结构。PL激发光谱揭示了与InGaN预层相关的吸收和载流子转移过程，这产生了额外的复合途径，导致PL光谱的高能量侧的特征。时间分辨PL研究表明，这种复合对主要发光特征的温度敏感性较弱，因此可能是在300 K下测量的PL强度增强的原因。单色阴极发光（CL）图像显示源自“V”缺陷的高能量特征。因此，这表明InGaN预层可以为预层中的载流子提供转移机制，使其进入“V”缺陷面上的半极性量子阱。可替代地，高能量发射可以由堆叠的基部处的QW产生，该QW具有与其余QW显著不同的参数。（© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA，魏因海姆）
In this paper we report on the effects of including of an InGaN prelayer in an InGaN/GaN multiple quantum well (MQW) structure. Two equivalent 10 period In0.16Ga0.84N MQW structures were studied, one with a 24 nm thick In0.05Ga0.95N prelayer, one without. X‐ray diffraction measurements showed no evidence of strain relaxation in the structure containing the prelayer, while AFM revealed a 15% increase in average diameter of “V”‐defects. Temperature dependent photoluminescence (PL) showed the MQW structure, with the prelayer, to exhibit a higher room temperature internal quantum efficiency than the reference structure. PL excitation spectroscopy revealed an absorption and carrier transfer process associated with the InGaN prelayer, which created an additional recombination pathway resulting in a feature on the high energy side of the PL spectrum. Time‐resolved PL studies showed that this recombination had a weaker temperature sensitivity to that of the primary luminescence feature, and thus may be responsible for the enhanced PL intensity measured at 300 K. Monochromatic cathodoluminescence (CL) images showed the high energy feature originated from the “V”‐defects. It is thus suggested that the InGaN prelayer may provide a transfer mechanism for carriers in the prelayer into the semi‐polar QWs on the “V”‐defect facets. Alternatively the high energy emission may arise from QWs at the base of the stack that have parameters that are significantly different from the rest of the QWs. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)