Olorunsola Oluwatobi, Ojo Solomon, Abernathy Grey, Zhou Yiyin, Amoah Sylvester, Grant P C, Dou Wei, Margetis Joe, Tolle John, Kuchuk Andrian, Du Wei, Li Baohua, Zhang Yong-Hang, Yu Shui-Qing
Microelectronics-Photonics Program, University of Arkansas, Fayetteville, AR 72701, United States of America.
Department of Electrical Engineering, University of Arkansas, Fayetteville, AR 72701, United States of America.
Nanotechnology. 2021 Nov 30;33(8). doi: 10.1088/1361-6528/ac38e4.
In this work, a SiGeSn/GeSn/SiGeSn single quantum well was grown and characterized. The sample has a thicker GeSn well of 22nm compared to a previously reported 9nm well configuration. The thicker well leads to: (i) lowered ground energy level in Γ valley offering more bandgap directness; (ii) increased carrier density in the well; and (iii) improved carrier collection due to increased barrier height. As a result, significantly enhanced emission from the quantum well was observed. The strong photoluminescence (PL) signal allows for the estimation of quantum efficiency (QE), which was unattainable in previous studies. Using pumping-power-dependent PL spectra at 20K, the peak spontaneous QE and external QE were measured as 37.9% and 1.45%, respectively.
在这项工作中，生长并表征了一个SiGeSn/GeSn/SiGeSn单量子阱。与之前报道的9nm阱结构相比，该样品具有更厚的22nm的GeSn阱。更厚的阱导致：（i）Γ谷中的基态能级降低，提供了更高的带隙直接性；（ii）阱中载流子密度增加；以及（iii）由于势垒高度增加，载流子收集得到改善。结果，观察到量子阱的发射显著增强。强的光致发光（PL）信号使得能够估计量子效率（QE），这在以前的研究中是无法实现的。使用20K下与泵浦功率相关的PL光谱，测得峰值自发QE和外部QE分别为37.9%和1.45%。
