Transport and recombination properties of group-III doped SiCNTs

Abstract

Silicon carbide nanotubes (SiCNTs) have attracted extensive scientific and commercial interest due to their excellent properties. Based on the first principles, the lattice and energy band structure of group III element-doped SiCNTs are studied, it is found that when the electronegativity of the doped atoms is less than that of the surrounding atoms, except for an acceptor energy level near the top of the valence band, a deep impurity level is also produced near the conduction band. Numerical simulation results show that the substitution of silicon is beneficial to improve the transport performance of SiCNTs, while the substitution of C atoms is more beneficial to the improvement of recombination performance. Further analysis showed that the dominant role in the transport process of doped SiCNTs is the optical phonon scattering mechanism. The increase in non-equilibrium minority carrier lifetime when C is substituted is due to the large acceptor ionization energy, which reduces the trapping rate of holes. This will improve the photon excitation and radiation performance of doped SiCNTs. • In SiCNTs, a shallow level is introduced when Si are replaced, and the deep levels are introduced when C are replaced. • Conductivity mainly depends on the hole concentration, and phonon scattering plays a leading role in the migration mechanism. • When C was replaced, the hole capture rate decrease and electron lifetime increase with the increase of ionization energy. • The substitution of silicon is beneficial to improve the transport performance of SiCNTs. • The substitution of C atoms is more beneficial to the improvement of recombination performance.