Enhancement of free-carrier screening due to tunneling in coupled asymmetric GaN/AlGaN quantum discs
Enhancement of free-carrier screening due to tunneling in coupled asymmetric GaN/AlGaN quantum discs
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由于耦合非对称 GaN/AlGaN 量子盘中的隧道效应增强了自由载流子屏蔽
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
T. Kang
中科院分区：
文献类型：
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作者：
Kwan H. Lee;J. Na;R. Taylor;S. Yi;S. Birner;Y. S. Park;C. Park;T. Kang
我们利用时间积分和时间分辨微光致发光测量，在三维多带 k∙p 计算模型的支持下，对具有嵌入式 AlGaN 势垒的耦合不对称 GaN 量子盘中的自由载流子筛选进行了研究。我们观察到，随着光激发的增加，载流子寿命缩短，发射能量蓝移。这源于光生自由载流子对量子盘中内置压电场和热释电场的屏蔽。由于载流子从较小圆盘到较大圆盘的非共振隧道效应，自由载流子屏蔽在较大圆盘中得到增强。计算模型与实验结果非常吻合。
We present an investigation of free-carrier screening in coupled asymmetric GaN quantum discs with embedded AlGaN barriers using time-integrated and time-resolved microphotoluminescence measurements, supported by three-dimensional multiband k∙p computational modeling. We observe that with increasing optical excitation the carrier lifetime decreases and emission energy blueshifts. This originates from the screening of built-in piezo- and pyroelectric fields in the quantum discs by photogenerated free carriers. Due to nonresonant tunneling of carriers from the smaller disk to the larger disk, free-carrier screening is enhanced in the larger disk. Computational modeling was in good agreement with the experimental results.