The effect of C, Si, N, and P impurities on structural and electronic properties of armchair boron nanotube

The structural and electronic properties of nonmetal atoms (X = C, N, Si, P) doped (6,0) boron nanotube (BNT) have been considered in a systematic study by performing periodic spin polarized density functional theory (DFT) calculations. The studies showed that cylindrical shape of the nanotube is changed by doping, except for C substitution. Notably, all the substitution processes are endothermic and the C-substituted becomes energetically more stable than the other dopants. It is revealed that the C-doped BNT is semi-metal, whereas the nanotube in the presence of the other dopants remains semiconductor. Hence, the substitution is an effective way in narrowing band gap of the nanotube. Doping by N atom changes the band gap from indirect to direct, which can be suitable for optical applications. Thus, electronic structure of the tube has been controlled by type of the dopant atoms. Our study predicted that the BNTs in the presence of the dopants are promising candidate as interconnects for nano-devices as well as field emission devices.