Evaluation of thermal conductivity characteristics in Si nanowire covered with oxide by UV Raman spectroscopy

Abstract

Thermal conductivity characteristics of Si nanowires (SiNWs) treated with thermal oxidation before and after a subsequent Ar+ ion irradiation process were evaluated by UV Raman spectroscopy, in order to investigate the impact of interfacial oxide-induced lattice disorder. Laser-power-dependent Raman spectroscopy showed that the rise in temperature caused by laser heating of SiNWs is suppressed by the Ar+ ion irradiation process. It is considered that this suppression of an increase in temperature is caused by the Ar+ ion irradiation breaking bonds at the SiO2/SiNW interface. These results indicate that not only roughness and defects but also bonding characteristics at SiO2/SiNW interfaces should be carefully considered to achieve a low value of thermal conductivity for next-generation SiNW thermoelectric devices. To realize phonon scattering in SiNWs efficiently, optimization of thermal oxidation is necessary.