Abstract
In this paper, we report on the impact of InAs quantum dots' (QDs) position within InGaAs strain reducing layer on their structural and optical properties. Morphological investigation revealed that the QD' size and density are strongly dependent on the InGaAs underlying layer's thickness. Additionally, comprehensive spectroscopic study by room temperature photoretlectance spectroscopy (PR) and temperature dependent photoluminescence (PL) showed that indium segregation and strain driven alloy phase separation alter both the QDs and their surrounding materials. Embedding or covering the InAs QDs by InGaAs has been found to improve their overall properties including an extended emission wavelength up to 1.3 mu m. However a pronounced degradation has been observed when growing them on the top of the strain reducing layer, resulting in a broadened size distribution and atypical temperature dependent emission energy and linewidth. (C) 2013 Elsevier B.V. All rights reserved.