Optical, electrical, and structural properties of Ta-doped SnO2 films against substrate temperature using direct current magnetron sputtering

Abstract

Ta-doped SnO2 (TTO) films were deposited at 3 × 10−3 Torr pressure from the 6 wt. % Ta2O5-doped SnO2 target at temperatures of 30–500 °C in Ar sputtering gas. The Ta dopants in the SnO2 host lattice were detected via X-ray photoemission, EDX mapping, and photoluminescence spectra. The Ta5+–Sn4+ substitution formed the OOx at VOxsites in the host lattice and the substitution occurred at deposition temperatures greater than 200 °C. The substitution leads to a decrease in the amount of VOx in the SnO2 lattice corresponding to the preferred rutile SnO2 (110) lattice reflection in the X-ray diffraction patterns. The ultraviolet-visible transmittance in visible light was approximately 80%. The lowest resistivity achieved was 2.0 × 10−3 Ω.cm, with a carrier concentration of 1.28 × 1020 cm−3 and carrier mobility of 24.5 cm2V−1s−1. The integration of the TTO-400 film with (n- and p-) Si exhibited an excellent photoelectric effect.