Polarization controlled emisson from closely stacked InAs/GaAs quantum dots

Abstract

AbstractWe have controlled the electronic states of closely‐stacked InAs/GaAs quantum dots with a 4.0 nm spacer layer and investigated the optical gain characteristics. With an increase in the stacking‐layer number (SLN), the [001] transverse‐magnetic (TM) polarization component increases as well as the linear polarization anisotropy in the (001) plane becomes remarkable. These SLN‐dependent polarization characteristics result from the valence‐band mixing induced by the vertically‐coupled electronic states in stacked QDs. We have systematically studied polarized electroluminescence properties of a semiconductor‐optical amplifier devise containing 30‐stacked InAs/GaAs QDs. The net modal gain was analyzed by using the Hakki‐Paoli method. The injection current dependence of the gain spectra shows a state filling effect and a change in the contribution of the TM polarization component. The polarization insensitive gain feature within ±1 dB has been achieved in the low injection current condition. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)