Effects of heat treatment on the chemical states of O1s and Sn3d at the surface of SnOx:F films by APCVD

X-ray photoelectron spectroscopy (XPS) was carried out to investigate the chemical states of O1s and Sn3d at the surface of SnOx:F films as-deposited and post-heated at 700 °C for 202 s and 262 s. The effects of heat treatment on the surface chemistry of SnOx:F films were discussed for the analysis of conductivity. The results show that there are three kinds of components of O1s and Sn3d at the surface and the binding energy of all components moves to higher values after post-heating. The ratio [OI]/[OII] at the surface decreases from 1.80 for the as-deposited film to 0.74 for the film heated for 262 s. The as-deposited films exhibit evident non-stoichiometry with relative concentration [O]/[Sn] equal to 1.46. After heat treatment, the relative concentration is higher than the stoichiometry value of 2.

► Ratio [OI]/[OII] decreases from 1.80 to 0.74 after heat treament.
► As-deposited films exhibit evident non-stoichiometry with [O]/[Sn] of 1.46.
► After heat treatment, the ratio [O]/[Sn] at the surface increases a lot.
► Corresponding O1s and Sn3d peaks move to higher energy after heat treatment.