Carrier transport and collection was investigated in strained Si1-xGex/Si(100) double quantum wells (QWs) separated by a Si barrier. Steady-state photoluminescence (PL) revealed a clear spectral dominance switch of PL between the two QWs as the Si barrier was systematically varied. Time-of-flight luminescence spectroscopy was used to estimate the mean drift velocity of carriers in terms of the luminescence rise time difference between the two QWs. Carrier collection efficiency was found to be dependent on the well width, which was obtained from the luminescence intensity difference.