Abstract
Photoluminescence is reported in strained Si1−xGex/Si(100) coupled double quantum well (CDQW) systems. Systematic red shift of luminescence energy was found in symmetric CDQWs with decreasing width of the Si barrier centered at the DQW, the characteristics of which were used to determine the band offsets. The total and valence‐band discontinuities, ΔEcEv=156 meV and ΔEv=149±1 meV, were obtained, suggesting that the band alignment is of type I for x=0.177. Variation of the inserted Si barrier width in asymmetric CDWs revealed well‐resolved spectral evolution due to the reduction in tunneling‐controlled carrier escape competing with the radiative recombination.