p-type conduction in nitrogen-doped SnO2 films grown by thermal processing of tin nitride films

p-type nitrogen-doped SnO2 (SnO2:N) films were grown by thermal processing of amorphous tin nitride films at temperatures between 350 and 500 ∘C in flowing O2–Ar gas mixture. From high-resolution X-ray photoelectron spectroscopy (XPS) and X-ray diffraction patterns, it is deduced that the N atoms replace the O atoms in the SnO2 lattice. The N dopant is more tightly bound in SnO2:N at higher thermal oxidation temperatures deduced from the XPS results. The hole concentration obtained at an oxidation temperature of 400 ∘C is 1.87×1019 cm−3, which is dramatically enhanced compared to previous reports. Our results indicate that the high-temperature thermal oxidation of tin nitride is a facile and effective route to alleviate the self-compensation effect, reduce the content of γ-N2 double donors, and reinforce the stability of N dopant in the SnO2:N films.