Optical properties of vertically stacked InAs island layers grown on (311)A/B and (001) GaAs substrates
The optical properties of vertically stacked InAs island layers grown by molecular beam epitaxy on (311)A/B and (001) GaAs substrates have been studied by means of photoluminescence (PL) and transmission electron microscopy (TEM) measurements. These properties were systematically investigated as a function of spacer layer thickness, orientation, and temperature. Spacer layer thickness variation exhibits influence on PL spectra for all orientations. Differences in peak shape, position, amplitude and integrated photoluminescence have also been observed for all surfaces. The results show an increase of integrated PL intensity of ?5 times and a decrease of spectral linewidth compared with a single set of islands, suggesting a possible electronic coupling between the layers. In addition, in the case of (311)A, the structure does not exhibit QD formation.
vertically stacked inas island layers oprical properties