نوع مقاله : مقاله پژوهشی
1 دانشگاه حکیم سبزواری
2 گروه فیزیک، دانشگاه پیام نور، صندوق پست 4697-19395 تهران, ایران
عنوان مقاله [English]
In this paper, electronic properties of nano-sheets of silicon carbide, germanium carbide and tin carbide have been investigated. The calculations were performed based on the density functional theory (DFT) using full potential augmented plane wave (FP-LAPW) method. In our calculation we used GGA, LDA and TB-mBJ approximations for the exchange-correlation potential. Density of states calculations shows that the carbon p-orbitals have the highest contribution to the conducting and valance bands in the three nano-sheets. The band structure calculations show that the band gap in SiC, GeC and SnC nano-sheets is direct, direct and indirect, respectively. The band gaps calculated by the TB-mBJ approximation for these nano-sheets were obtained about 3.31, 2.93 and 1.38 eV, respectivly, which are significantly higher than the band gap calculated by the two other approximations. Therefore, due to the direct and relatively large energy bands, SiC and GeC nano-sheets can be considered in the nano electro-optic devices. The percentage of ionization of the bonds was investigated using Pauli's relation and electron density calculations. The results show that the type of the bonds is covalent and the percentage of ionization of the bonds in the SiC, GeC and SnC are 10, 7 and 8 percent, respectively.