Theoretical gain of strained GeSn[sub 0.02]/Ge[sub 1−x−y[sup ʹ]]Si[sub x]Sn[sub y[sup ʹ]] quantum well laser

• Main Authors: Zhu, Yuan-Hui, Xu, Qiang, Fan, Weijun, Wang, Jian-Wei
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Electrical and electronic engineering
• Online Access: https://hdl.handle.net/10356/100829; http://hdl.handle.net/10220/18169
• Institution: Nanyang Technological University

Using effective-mass Hamiltonian model of semiconductors quantum well structures, we investigate the electronic structures of the -conduction and L-conduction subbands of GeSn/GeSiSn strained quantum well structure with an arbitrary composition. Our theoretical model suggests that the band structure could be widely modified to be type I, negative-gap or indirect-gap type II quantum well by changing the mole fraction of -Sn and Si in the well and barrier layers, respectively. The optical gain spectrum in the type I quantum well system is calculated, taking into account the electrons leakage from the -valley to L-valley of the conduction band. We found that by increasing the mole fraction of -Sn in the barrier layer and not in the well layer, an increase in the tensile strain effect can significantly enhance the transition probability, and a decrease in Si composition in the barrier layer, which lowers the band edge of -conduction subbands, also comes to a larger optical gain.