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 stra ined layer superlattices and a Si-9/Ge-6 strain-symmetrized superlatti ce were fabricated using electron beam lithography and reactive ion et ching. They were investigated by photoluminescence and photoreflectanc e. It was found for the first time that the quantum efficiency of opti cal 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.