Theoretical studies on the optical properties of group-III elements doped SiCNTs

Silicon carbide nanotubes (SiCNTs) have broad application prospects in optoelectronic devices. Based on first principles calculation, the influence of group III elements X (X = B, Al, Ga and In) doping on the optical properties of SiCNTs was studied. At 250-620 nm, because the hole concentration of XC-SiCNTs (when C is substituted) is less than that of XSi-SiCNTs (when Si is substituted), the minority carrier lifetime is longer than that of XSi-SiCNTs, therefore, the absorption peak of XC-SiCNTs is low and wide, while that of XSi-SiCNTs is high and narrow. Starting from 400 THz to 500 THz, with the increase of photo-generated carriers, the photoconductivity of XSi-SiCNTs and XC-SiCNTs increases, reaching the maximum at 700-800 THz. As the recombination rate increases, the conductivity begins to decrease, and it drops to a minimum near 1000 THz. Both dielectric constant and reflectivity show that SiCNTs doped with Si sites exhibit metallic characteristics at 340-380 nm.

Automated summary

The influence of group III elements doping on the optical properties of silicon carbide nanotubes was studied using first principles calculation. It was found that the hole concentration of XC-SiCNTs is less than that of XSi-SiCNTs, leading to longer minority carrier lifetime in XC-SiCNTs. Additionally, the photoconductivity of both XSi-SiCNTs and XC-SiCNTs increases with the increase of photo-generated carriers, reaching a maximum at 700-800 THz.