PHOTOLUMINESCENCE AND PHOTOREFLECTANCE STUDY OF SI/SI0.91GE0.09 AND SI-9/GE-6 QUANTUM DOTS

Nanometer-scale quantum dots based on a series of Si/Si0.91Ge0.09 strained layer superlattices and a Si-9/Ge-6 strain-symmetrized superlattice were fabricated using electron beam lithography and reactive ion etching. They were investigated by photoluminescence and photoreflectance. It was found for the first time that the quantum efficiency of optical emission from the quantum well layers increased by over two orders of magnitude when the quantum dot sizes were reduced to less than or equal to 100 nm