Design, Theoretical, and Experimental Investigation of Tensile-Strained Germanium Quantum-Well Laser Structure
Design, Theoretical, and Experimental Investigation of Tensile-Strained Germanium Quantum-Well Laser Structure
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DOI：
10.1021/acsaelm.1c00660
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发表时间：
2021-10-14
影响因子：
4.7
通讯作者：
Ochalski, Tomasz J.
中科院分区：
文献类型：
--
作者：
Hudait, Mantu K.;Murphy-Armando, Felipe;Ochalski, Tomasz J.
本文首次从理论上和实验上研究了GaAs衬底上应变和带隙工程外延锗（epsilon-Ge）量子阱（QW）激光结构。在本设计中，我们利用InGaAs层同时提供Ge（0.7-1.96%）的拉伸应变以及足够的光学和载流子约束的能力。在注入载流子浓度为3 × 10（18）至9 × 10(19) cm（-3）的情况下，利用基于第一线原理的30波段kp电子结构理论，计算了epsilon-Ge QW激光结构中占主导地位的直接带间增益、阈值电流密度（Jth）和损耗机制。epsilon-Ge量子阱中较高的应变增加了更高波长的增益；然而，由于存在避免应变松弛的临界层厚度，较高的应变要求厚度减小。此外，我们预测300 a /cm(2)的J（th）可以降低到
Strain and band gap engineered epitaxial germanium (epsilon-Ge) quantum-well (QW) laser structures were investigated on GaAs substrates theoretically and experimentally for the first time. In this design, we exploit the ability of an InGaAs layer to simultaneously provide tensile strain in Ge (0.7-1.96%) and sufficient optical and carrier confinement. The direct band-to-band gain, threshold current density (Jth), and loss mechanisms that dominate in the epsilon-Ge QW laser structure were calculated using firstprinciples-based 30-band k.p electronic structure theory, at injected carrier concentrations from 3 x 10(18) to 9 x 10(19) cm(-3). The higher strain in the epsilon-Ge QW increases the gain at higher wavelengths; however, a decreasing thickness is required by higher strain due to critical layer thickness for avoiding strain relaxation. In addition, we predict that a J(th) of 300 A/cm(2) can be reduced to