Comprehensive investigation of optical and electronic properties of tunable InAs QDs optically active at O-band telecommunication window with (In)GaAs surrounding material

In this paper, we report on the impact of InAs quantum dotsʹ (QDs) position within InGaAs strain reducing layer on their structural and optical properties. Morphological investigation revealed that the QDʹ size and density are strongly dependent on the InGaAs underlying layerʹs thickness. Additionally, comprehensive spectroscopic study by room temperature photoreflectance 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 μm. 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.