Band Alignment in ${\mathrm{Si}}_{1-\mathit{y}}{\mathrm{C}}_{\mathit{y}}/\mathrm{Si}\left(001\right)$ and ${\mathrm{Si}}_{1-\mathit{x}}{\mathrm{Ge}}_{\mathit{x}}/{\mathrm{Si}}_{1-\mathit{y}}{\mathrm{C}}_{\mathit{y}}/\mathrm{Si}\left(001\right)$ 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 ${\mathrm{Si}}_{1-y}{\mathrm{C}}_y/\mathrm{Si}$ and ${\mathrm{Si}}_{1-x}{\mathrm{Ge}}_x/{\mathrm{Si}}_{1-y}{\mathrm{C}}_y/\mathrm{Si}$ heterostructures. We confirm a type I alignment for ${\mathrm{Si}}_{1-y}{\mathrm{C}}_y/\mathrm{Si}$ and report the first observation of an elastic strain induced type I to type II transition in ${\mathrm{Si}}_{1-y}{\mathrm{C}}_y/\mathrm{Si}$ quantum wells. Results for a ${\mathrm{Si}}_{0.84}{\mathrm{Ge}}_{0.16}/{\mathrm{Si}}_{0.99}{\mathrm{C}}_{0.01}/\mathrm{Si}$ structure support a type II 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 ${\mathrm{Si}}_{1-y}{\mathrm{C}}_y/\mathrm{Si}$ with $y=0.5\mathrm{}\%or1\%$.