We have systematically studied the electronic structure of the ordered Si-C alloys, fourteen models were created according to the different carbon contents. The linear muffin-tin orbitals method was used to calculate their energy band informations. The functional relation of band gap upon carbon contents conflicts with the point of view of Soref [J. Appl. Phys. Lett. 56 (1990) 734], but agrees well with that of Alexander's [Phys. ...
