Chemical surface passivation of 3C-SiC nanocrystals: A first-principle study

The effect of the chemical surface passivation, with hydrogen atoms, on the energy band gap of porous cubic silicon carbide (PSiC) was investigated. The pores are modeled by means of the supercell technique, in which columns of Si and/or C atoms are removed along the [001] direction. Within this supercell model, morphology effects can be analyzed in detail. The electronic band structure is performed using the density functional theory based on the generalized gradient approximation. Two types of pores are studied: C-rich and Si-rich pores surface. The enlargement of energy band gap is greater in the C-rich than Si-rich pores surface. This supercell model emphasizes the interconnection between 3C-SiC nanocrystals, delocalizing the electronic states. However, the results show a clear quantum confinement signature, which is contrasted with that of nanowire systems. The calculation shows a significant response to changes in surface passivation with hydrogen. The chemical tuning of the band gap opens the possibility plenty applications in nanotechnology.