Photoluminescence and micro-imaging study of optically anisotropic InP self-assembled quantum dots

The optical properties of InP self-assembled quantum dots (SADs) were investigated under band-to-band excitation of the Ga0.5In0.5P matrix by means of macro- (conventional) and micro-photoluminescence (μ-PL) spectroscopy. We clearly observed that the number of bright spots in the μ-PL images of InP SADs depends on the detection energy, reflecting the size distribution of the SADs. The macro-photoluminescence spectra and μ-PL images of the InP SADs were found to exhibit a strong optical anisotropy with two-fold symmetry, which reflects the anisotropic structure of the Ga0.5In0.5P matrix due to the Cu-PtB type long-range ordering.