Band alignment in Si1-yCy/Si(001) and Si1-xGex/Si1-yCy/Si(001) quantum wells by photoluminescence under applied [100] and [110] uniaxial stress

We use a novel wafer bending technique to study band alignment under applied uniaxial stress in Si1-yCy/Si and Si1-xGex/Si(1-y)Cy/Si heterostructures. We confirm a type I alignment for Si1-yCy/Si and report the first observation of an elastic strain induced type I to type II transition in Si1-yCy/Si quantum wells. Results for a Si0.84Ge0.16/Si0.99C0.01/Si structure support a type IT transition between the SiGe valence band and the SiC conduction band. These results also indicate a conduction band offset of at most 65% of the band gap difference for Si1-yCy/Si with y=0.5% or 1%.