Effect of inter-wall coupling on the electronic structure and optical properties of group-III doped SiCNTs

The inter-wall coupling mechanism is studied by comparing the group-III doped on the inner and outer walls of DWSiCNTs and SWSiCNTs differs in band structure and optical properties. For DWSiCNTs, B and Ga atoms doping the outer wall is easier to dope, while Al and In doping the inner wall is easier to achieve. DWSiCNTs doped with group-III atoms enhances the inter-wall coupling, and the coupling effect of the inner wall doped DWSiCNTs is stronger than that of the outer wall doped. The inner wall doping has a more obvious regulatory effect on the inter-wall coupling of DWSiCNTs. The absorption and photoconductivity show that in the visible and ultraviolet bands, the intrinsic conductivity peaks of DWSiCNTs are larger and wider. This is because the coupling effect increases the electron transition probability of doped DWSiCNTs, making the carrier concentration greater than SWSiCNTs, and the minority carrier lifetime is longer.