Salhi A, Alshaibani S, Alaskar Y, Albrithen H, Albadri A, Alyamani A, Missous M
School of Electrical and Electronic Engineering, The University of Manchester, Sackville Street, Manchester, M13 9PL, UK.
National Center for Nanotechnology and Advanced Materials, KACST, Riyadh, 11442, Saudi Arabia.
Nanoscale Res Lett. 2019 Feb 1;14(1):41. doi: 10.1186/s11671-019-2877-2.
In this work, we investigate the optical properties of InAs quantum dots (QDs) capped with composite InAlAs/GaAsSb strain-reducing layers (SRLs) by means of high-resolution X-ray diffraction (HRXRD) and photoluminescence (PL) spectroscopy at 77 K. Thin InAlAs layers with thickness t = 20 Å, 40 Å, and 60 Å were inserted between the QDs and a 60-Å-thick GaAsSb layer. The type II emissions observed for GaAsSb-capped InAs QDs were suppressed by the insertion of the InAlAs interlayer. Moreover, the emission wavelength was blueshifted for t = 20 Å and redshifted for t ≥ 40 Å resulting from the increased confinement potential and increased strain, respectively. The ground state and excited state energy separation is increased reaching 106 meV for t = 60 Å compared to 64 meV for the QDs capped with only GaAsSb SRL. In addition, the use of the InAlAs layers narrows significantly the QD spectral linewidth from 52 to 35 meV for the samples with 40- and 60-Å-thick InAlAs interlayers.
在本工作中，我们通过77K下的高分辨率X射线衍射（HRXRD）和光致发光（PL）光谱研究了用InAlAs/GaAsSb复合应变降低层（SRL）包覆的InAs量子点（QD）的光学性质。厚度t = 20 Å、40 Å和60 Å的薄InAlAs层插入量子点和60 Å厚的GaAsSb层之间。插入InAlAs中间层抑制了GaAsSb包覆的InAs量子点观察到的II型发射。此外，由于限制势增加和应变增加，发射波长在t = 20 Å时发生蓝移，在t≥40 Å时发生红移。与仅用GaAsSb SRL包覆的量子点的64 meV相比，基态和激发态能量分离增加，对于t = 60 Å达到106 meV。此外，对于具有40 Å和60 Å厚InAlAs中间层的样品，使用InAlAs层显著地将量子点光谱线宽从52 meV窄化到35 meV。
