Study of carrier dynamics of vertically aligned InAs/GaAsSb quantum dot structures



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 correspondent 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 the promising candidates for novel optoelectronic device application. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)