Firstly, electronic structures of perfect wurtzite 4H—SiC were calculated by using a first-principles ultra-soft pseudo-potential approach to the plane wave based upon density functional theory, and the structural changes, band structures and density of states were studied. Then the defect-energy level of the carbon vacancy in the band gap was examined by substituting carbon into 4H-SiC with carbon vacancy. The calculated results indicated the new defect-energy level generated by the carbon vacancy, and its location in the band gap in 4H-SiC, which had the character of a deep acceptor. A proper explanation for green luminescence in 4H-SiC was given on the basis of the calculated results, which were in good agreement with the measured results.

First-Principle Calculation on the Defect Energy Level of Carbon Vacancy in 4H-SiC. R.X.Jia, Y.M.Zhang, Y.M.Zhang: Chinese Physics B, 2010, 19[10], 107105