Abstract
Using density functional theory (DFT) we report results for the electronic structure and vibrational dynamics of hydrogenated silicon carbide (001) (3 x 2) surfaces with various levels of hydrogenation. These results were obtained using density functional theory with a generalized gradient exchange correlation function. The calculations reveal that metallization can be achieved via hydrogen atoms occupying the second silicon layer. Further increase of hydrogen occupation on the second silicon layer sites results in a loss of this metallization. For the former scenario, where metallization occurs, we found a new vibrational mode at 1870 cm(-1), which is distinct from the mode associated with hydrogen atoms on the first layer. Furthermore, we found the diffusion barrier for a hydrogen atom to move from the second to the third silicon layer to be 258 meV. (c) 2012 Elsevier B.V. All rights reserved.