A novel precursor towards buffer layer materials: the first solution based CVD of zinc oxysulfide†
We report the first solution based deposition of zinc oxysulfide, Zn(O,S), thin films via aerosol-assisted chemical vapour deposition (AACVD) facilitated by the use of a specifically designed precursor: [Zn8(SOCCH3)12S2] (1). This buffer layer material, synthesised from the dual source AACVD reaction of 1 with ZnEt2 and MeOH was analysed via X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray (EDX) analysis, scanning electron microscopy (SEM), Hall effect measurements and UV/vis spectroscopy. The film was highly transparent (>90%), conductive (ρ = 0.02998 Ω cm) and had a high charge carrier concentration (1.36 × 1019 cm−3), making it a good contendor as a buffer layer in thin film photovoltaics. In an additional study, large area films were deposited and mapped to correlate compositional variation to optoelectronic properties.