Strain-induced exciton localized states in quantum well

Abstract

We use AlAs sacrificial layer etching technology to peel a film of In0.15Ga0.85As/GaAs single quantum wells (QWs) from a GaAs substrate and transfer the film to a Si wafer covered with randomly distributed Au nanoparticles. In this way, local strains are introduced into the QW film, which leads to the formation of the exciton confinement potential. From them, we have observed very sharp emission lines in photoluminescence (PL) spectra and local PL bright spots in space. The PL is proved to be from localized exciton emission in a potential energy funnel. We can also introduce the localized strain in the QW film using a micropillar array of an electron beam resist and observe similar narrow emission lines. The method to achieve localized exciton states is a controllable way and it will further expand the application of traditional semiconductor QWs in optical quantum devices.