PHOTOLUMINESCENCE FROM SI/SI0.87GE0.13 MULTIPLE-QUANTUM-WELL WIRES

This paper reports a low temperature photoluminescence study of the optical properties of a series of dry etched free standing strained layer Si/Si0.87Ge0.13 multiple quantum well wires with lateral dimensions between 40nm and 500nm. The results show that dry etching induces partial strain relaxation. An enhanced electron-hole droplets emission from the Si layers with reducing wire width was observed due to both the extra surface roughness introduced during the etching process, which accelerates the nucleation of the droplets formation, and the effect of lateral confinement. A new feature at 1.131eV at 4K related to unknown impurity states located at the heterointerfaces was also detected