  We report on the systematic investigation of the optical properties of a
selectively grown quantum dot gain material assisted by block-copolymer
lithography for potential applications in active optical devices operating in
the wavelength range around 1.55 um and above. We investigated a new type of
diblock copolymer PS-b-PDMS (polystyrene-block-polydimethylsiloxane) for the
fabrication of silicon oxycarbide hard mask for selective area epitaxy of
InAs/InP quantum dots. An array of InAs/InP quantum dots was selectively grown
via droplet epitaxy. Our detailed investigation of the quantum dot carrier
dynamics in the 10-300 K temperature range indicates the presence of a density
of states located within the InP bandgap in the vicinity of quantum dots. Those
defects have a substantial impact on the optical properties of quantum dots.
