Resolving decay-time dependent photoluminescence induced by phonon-dressed excitons in ZnO
Resolving decay-time dependent photoluminescence induced by phonon-dressed excitons in ZnO
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解决 ZnO 中声子修饰激子引起的衰变时间依赖性光致发光
DOI：
10.1103/physrevmaterials.6.104607
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发表时间：
2022
影响因子：
3.4
通讯作者：
Matsuda Iwao
中科院分区：
文献类型：
--
作者：
Yukawa Ryu;Yamamoto Susumu;Arita Ren;Minami Yuki;Yamanoi Kohei;Ozawa Kenichi;Sakamoto Kazuyuki;Shimizu Toshihiko;Sarukura Nobuhiko;Matsuda Iwao
在室温下对ZnO晶体进行了时间分辨光致发光（PL）实验，以阐明近带边（NBE）发射的起源。的PL光谱的时间分布表现出不同的衰减速率的两条曲线的结构，并合理地再现由双指数函数，表明有至少两个不同的衰减时间在NBE发射的起源。通过考虑自由激子（FX）-纵向光学（LO）声子相互作用，分析了不同的激发态，发现快的和慢的衰减发射分别与较强和较弱的FX-LO声子耦合有关。我们提出，具有不同衰减时间的NBE发射与晶体缺陷有关;快速衰减的发射来自具有较高密度的缺陷或杂质的区域，而较慢的发射来自具有较好结晶度的区域。
Time-resolved photoluminescence (PL) experiments on ZnO crystals have been conducted at room temperature to elucidate the origins of a near-band edge (NBE) emission. A temporal profile of the PL spectra exhibits a two-curve structure with different decaying rates and is reproduced reasonably by a biexponential function, indicating that there are at least two origins with different decay times in the NBE emission. By taking free exciton (FX)–longitudinal optical (LO) phonon interactions into account in the analysis of the PL spectra, the faster and slower decaying emissions are found to be associated with stronger and weaker FX-LO phonon coupling, respectively. We propose that the NBE emissions with different decay times are related to crystal imperfections; the fast-decaying emission originates from the region with a higher density of defects or impurities, while the slower one is from the regions with better crystallinity.