A novel and potentially scalable CVD-based route toward SnO2:Mo thin films as transparent conducting oxides

In this report, we prepared transparent and conducting undoped and molybdenum-doped tin oxide (Mo–SnO₂) thin films by aerosol-assisted chemical vapour deposition (AACVD). The relationship between the precursor concentration in the feed and in the resulting films was studied by energy-dispersive X-ray spectroscopy, suggesting that the efficiency of doping is quantitative and that this method could potentially impart exquisite control over dopant levels. All SnO₂ films were in tetragonal structure as confirmed by powder X-ray diffraction measurements. X-ray photoelectron spectroscopy characterisation indicated for the first time that Mo ions were in mixed valence states of Mo(VI) and Mo(V) on the surface. Incorporation of Mo⁶⁺ resulted in the lowest resistivity of 7.3×10-3Ωcm, compared to pure SnO₂ films with resistivities of 4.3(0)×10-2Ωcm. Meanwhile, a high transmittance of 83% in the visible light range was also acquired. This work presents a comprehensive investigation into impact of Mo doping on SnO₂ films synthesised by AACVD for the first time and establishes the potential for scalable deposition of SnO₂:Mo thin films in TCO manufacturing.