Synthesis and systematic optical investigation of selective area droplet epitaxy of InAs/InP quantum dots assisted by block copolymer lithography

We report on the synthesis and systematic investigation of quantum dot based optical gain material potentially suitable for applications in active devices operating around a wavelength of 1.55 mu m and above. The quantum dots were selectively grown in a process assisted by block-copolymer lithography. We applied a new type of diblock copolymer, PS-b-PDMS (polystyrene-block-polydimethylsiloxane), which allows for the direct fabrication of a silicon oxycarbide hard mask used for lithography. Arrays of InAs/InP quantum dots were selectively grown via droplet epitaxy. Our detailed optical investigations of the quantum dot carrier dynamics in the 10-300 K temperature range indicate the presence of a significant density of defect states located within the InP bandgap and in the vicinity of the quantum dots. Those defects have a substantial impact on the optical properties of the quantum dots. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement