Wu Chun-Sheng, Wu Sheng-Chan, Yang Bo-Ting, Wu Zong Yu, Chou Yu Hsun, Chen Peter, Hsu Hsu-Cheng
Department of Photonics, National Cheng Kung University, No. 1, University Road, East District, Tainan 70101, Taiwan.
Hierarchical Green-Energy Materials (Hi-GEM) Research Center, National Cheng Kung University, No. 1, University Road, East District, Tainan 70101, Taiwan.
ACS Appl Mater Interfaces. 2021 Mar 24;13(11):13556-13564. doi: 10.1021/acsami.0c21738. Epub 2021 Mar 9.
We realized a single-mode laser with an ultra-high quality factor in individual cesium lead bromide (CsPbBr) perovskite micro-hemispheres fabricated by chemical vapor deposition. A series of lasing property analysis based on cavity size was reported under this material system. Due to good optical confinement capability of the whispering gallery resonant cavity and high optical gain of CsPbBr perovskite micro-hemispheres, single-mode lasing behavior was achieved with an ultra-high quality factor as large as 11,460 at room temperature. To study in detail the physical effects between lasing threshold and cavity, a set of cavity size dependence photoluminescence analyses were performed. We found that the lasing threshold increases while the cavity size decreases. Time-resolved PL analysis was conducted to confirm the relation between cavity size and lasing threshold. The larger cavity stands for longer PL lifetime and indicates easier-to-achieve carrier population inversion. Strong Purcell enhancement could be further investigated by the spontaneous emission coupling factor β and internal quantum efficiency as a function of cavity size. A high β-factor of 0.37 could be obtained from a 2.2 μm diameter hemisphere microcavity and a high Purcell factor of 14 in a 1.9 μm diameter hemisphere microcavity showing strong Purcell enhancement effect in our system.
我们在通过化学气相沉积法制备的单个溴化铯铅（CsPbBr）钙钛矿微半球中实现了具有超高品质因数的单模激光器。在该材料体系下报道了基于腔尺寸的一系列激光特性分析。由于回音壁共振腔良好的光学限制能力以及CsPbBr钙钛矿微半球的高光增益，在室温下实现了品质因数高达11460的单模激光行为。为了详细研究激光阈值与腔之间的物理效应，进行了一组腔尺寸依赖性光致发光分析。我们发现，随着腔尺寸减小，激光阈值增加。进行了时间分辨光致发光分析以确认腔尺寸与激光阈值之间的关系。较大的腔意味着更长的光致发光寿命，表明更容易实现载流子数反转。通过自发发射耦合因子β和作为腔尺寸函数的内量子效率，可以进一步研究强珀塞尔增强效应。在直径为2.2μm的半球形微腔中可获得0.37的高β因子，在直径为1.9μm的半球形微腔中可获得14的高珀塞尔因子，这表明我们的系统中存在强珀塞尔增强效应。
