Effect of Sn-substituted Ga and In dopant content on the structural, electrical, and optical properties of p-type X-doped SnO2 (X = Ga and In) films: Testing the photoelectronic effect of X-doped SnO2/n-Si junctions

Abstract

To achieve the best p-type conductive properties of X-doped SnO2 (X = Ga, In) SnO2 film, a 9% wt X2O3 in SnO2 target is the best content for substitution at X sites in the SnO2 host lattice by X dopant where optimum In content replaces Sn, eliminating the lattice distortion in undoped SnO2 film. Optimum Ga content that replaces Sn enhances the lattice distortion but does not break the host lattice. The Ga3+–Sn2+ and In3+–Sn2+ substitution was verified using measurements such as X-ray photoelectron spectroscopy, photoluminescence, and ultraviolet-visible spectroscopy; the data for the (110) to (101) tetragonal rutile lattice plane changes indicated this replacement. The best p-type conductive properties achieved were 3.0 × 10−1 Ω cm, 6.20 × 1018 cm−3, and 3.01 cm2 V−1 s−1, respectively, for GTO. The respective values of the TIO films were 2.6 × 10−1 Ω cm, 1.24 × 1018 cm−3, and 19.35 cm2 V−1 s−1 for the resistivity, hole concentration, and hole mobility, respectively. The I–V characteristics of the In/p-GTO/n-Si/In and In/p-TIO/n-Si/In devices under illumination showed the p-type conductive properties of the GTO and TIO films.