Excitonic luminescence from locally grown SiGe wires and dots

Abstract

SiGe quantum wells with finite lateral size have been fabricated using local molecular beam epitaxy through shadowing masks. Scanning electron microscope and transmission electron microscope micrographs show good quality of the mesas and an effective in situ passivation by overgrowth of the buried SiGe quantum wells at the sidewalls of the mesa due to the applied growth technique. Photoluminescence measurements show clear excitonic emission from the SiGe wires and dots with lateral widths down to 2 μm. Intensities per area from the mesas are comparable to intensities from reference areas, suggesting very effective protection of the carriers against possible nonradiative recombination at the sidewalls of the mesa.