Theoretical Analysis of Direct Transition in SiGe/GeSn Strained Quantum Well Structure by Finite Difference Method

Abstract

AbstractThis paper focuses on the potential of compressive strained group IV quantum well (QW) structure in photo sensitive devices specially photodetectors. Direct absorption characteristic in compressive strained SiGe/GeSn QW is determined with the help of Schrödinger equation. The Schrödinger equation for Г-valley, Heavy hole band and Light hole band is solved by finite difference method (FDM). Due to compressive strain, heavy hole (HH) band pushes upwards and light hole (LH) band lowers on addition of Sn concentration. Absorption coefficient of QW is evaluated by using Fermi’s golden rule. Result shows that significant absorption is obtained in short wave infrared range. HH to conduction band transition provides greater absorption than LH to conduction band transition. Result also shows that compressive strained GeSn become direct band gap in nature for Sn concentration greater than 0.15 (15 %).KeywordsQuantum WellFinite Difference methodFinite Difference MethodHeavy HoleLight HoleQuantum Well StructureThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.