LUMINESCENCE STUDY ON GE ISLANDS AS STRESSORS ON SI1-XGEX SI QUANTUM-WELL/

Photoluminescence (PL) study on lateral bandgap modulation in a Si1-xG ex/Si quantum well induced by self-assembled Ge islands which act as s tressors is carried out. It is confirmed that excitons are confined in the modulated quantum structure (MQS) in compressively strained regio ns induced by the Ge islands. Redshift of PL peaks from MQSs does not show a monotonic change but complicated behavior, i.e., it increases u p to Q = 3.7 ML and saturates above Q = 4.1 ML after once retrogressin g with the increase in the Ge coverage. The results are explained in t erms of elastic deformation due to Ge stressors and lattice relaxation in the Ge islands.