InAs/GaAs quantum dot lasers with dots in an asymmetric InxGa1-xAs quantum well structure

Abstract

We report the advantages of using InAs/GaAs quantum dots (QDs) having InxGa1-xAs asymmetric strain-released layers (ASRL) over the conventional InAs/GaAs QDs in long wavelength operation. Atomic layer molecular beam epitaxy was used to enhance the uniformity of InAs QDs in an InxGa1-xAs quantum well structure. The red shift as large as similar to 50 nm could be achieved by varying the thickness and indium composition of the InxGa1-xAs ASRL. We observed the longest wavelength of 1288 nm produced by the InAs/GaAs QD with ASRL by photoluminescence (PL). However, the stimulated emission gave the longest wavelength of 1206 nm, blue-shifted as large as similar to 82 nm from the PL peak at room temperature, which is attributed to the optical transitions via higher sub-band levels of the InAs/GaAs QDs. (c) 2006 Elsevier B.V. All rights reserved.