Carrier Dynamics of a Type-Ⅱ Vertically Aligned InAs Quantum Dot Structure with a GaAsSb Strain-Reducing Layer

摘要

The carrier dynamics of vertically aligned InAs/GaAsSb type-Ⅱ quantum dot (QD) structure are comprehensively analyzed by time-resolved photoluminescence (TRPL) in this study.A columnar InAs QD structure with an overgrown layer of GaAsSb is proposed to enhance the thermal stability and carrier lifetime through the type-Ⅱ energy band alignment and carrier tunneling effect.The carrier lifetimes of columnar QD structures were in accordance with the PL spectra in wavelength-dependent TRPL measurements because of the electronic coupling effect and the dot-size-dependent oscillator strength.The improved results in this work make columnar type-Ⅱ QDs promising candidates for novel optoelectronic device application.