Ab initio study of electronic structure of strained Si1-x-yGexCy/Ge(001)
CCAST (World Laboratory), P. O. Box 8730, Beijing 100080, PR China
2 Department of Physics, Xiamen University, Xiamen 361005, PR China
Revised: 3 May 1999
Published online: 13 August 2012
The ab initio pseudopotential method within the local density functional theory and virtual-crystal approximation is used to study the band gap of the SiGexCy (y 0.09) alloys on a Ge(001) substrate. The heterojunction discontinuities are also investigated in the framework of the average bond energy theory in conjunction with the deformation potential method. The calculated results show that the energy gap still remains indirect and only a small amount of C could cause the energy gap to be shrunk significantly. The top of the valence bands of the strained SiGexCy alloys on Ge(001) is significantly lifted and even could be greatly higher than that of Ge by the addition of small amounts of carbon. The trends of our results are consistent with other theoretical data.
PACS: 71.22.+i – Electronic structure of liquid metals and semiconductors and their alloys / 73.90.+f – Other topics in electronic structure and electrical properties of surfaces, interfaces, and thin films / 71.15.Hx – Pseudopotential method / 71.15.Mb – Density functional theory, local density approximation
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999