The universal tight binding method based on sp3s* basis functions is used to calculate the electronic structure of the ternary alloy Si1-x-yGexCy. The dependences of the fundamental band gaps (E(Λ), E(Δ), E(L), and E(X)) are obtained and investigated for small concentrations of carbon (0 ≤ y ≤ 0.05). It is found that the presence of carbon in the alloy Si1-x-yGe xCy, results in a very significant change (i.e., reduction) of the alloy bond length with a small change of the energy band gaps. The energy band gap increases upon adding carbon to the strained alloy. However, the energy band gap decreases upon adding carbon while keeping the alloy lattice matched to the substrate Si. The calculated band gaps are in good agreement with the limited available experimental data and ab initio results.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics