LUMINESCENCE STUDY ON INTERDIFFUSION IN STRAINED SI1-XGEX SI SINGLE QUANTUM-WELLS GROWN BY MOLECULAR-BEAM EPITAXY/

Optical investigation of interdiffusion at Si1-xGex/Si heterointerface s has been performed for the first time in strained Sil-xGex/Si single quantum wells (SQWs). Photoluminescence (PL) peak energy blue shift o f up to 22 meV due to interdiffusion-induced potential profile modulat ion was observed after annealing in vacuum. The diffusion coefficients obtained were found to closely follow an Arrhenius behavior with an a ctivation energy of 2.47+/-0.4 eV. Dramatic increase in the integrated PL intensity was observed in the annealed samples, as a result of the elimination of effective nonradiative centers. Strain relaxation was hardly observed even after 900-degrees-C annealing, indicating the unp recedented structural stability of SQWs in contrast to rather vulnerab le thick alloy layers. Anomalous peak red shift, probably due to surfa ce oxidation, was observed by annealing in N2 ambient.