Effect of H2 ambient annealing on silicon nanowires prepared by atmospheric pressure chemical vapor deposition

We report the effect of H2 ambient annealing on the microstructure and vibrational properties of silicon nanowires (SiNWs) grown by atmospheric pressure chemical vapor depositions. The SiNWs were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Field-Emission Scanning Electron Microscopy (FESEM) and High-Resolution Transmission Electron Microscopy (HRTEM). The HRTEM study revealed that the thickness of oxide sheath surrounded by core silicon decreased with increasing H2 ambient annealing and consequently the vibrational spectra were changed. In FTIR spectra, the transverse optic and longitudinal optic peak positions of Si–O symmetry and asymmetry showed a blue shift of the outer oxide of SiNWs. The Si–O–Si peak position remained unchanged at 1080 cm−1 while the integrated absorption of Si–O–Si vibration band decreased with increasing H2 flow rate.