Ta Doped SnO2 Transparent Conducting Films Prepared by PLD

Abstract

Transparent and conducting thin films of Ta-doped SnO 2 were fabricated on a glass substrate by a pulse laser deposition(PLD) method. The structural, optical, and electrical properties of these films were investigated as a function of doping level, oxygen partial pressure, substrate temperature, and film thickness. XRD results revealed that all the deposited films were polycrystalline and the intensity of the (211) plane of SnO 2 decreased with an increase of Ta content. However, the orientation of the films changed from (211) to (110) with an increase in oxygen partial pressure (40 to 100 mTorr) and substrate temperature. The crystallinity of the films also increased with the substrate temperature. The electrical resistivity measurements showed that the resistivity of the films decreased with an increase in Ta doping, which exhibited the lowest resistivity (ρ~1.1 × 10 −3 Ω·cm) for 10 wt% Ta-doped SnO 2 film, and then increased further. However, the resistivity continuously decreased with the oxygen partial pressure and substrate temperature. The optical bandgap of the 10 wt% Ta-doped SnO 2 film increased (3.67 to 3.78 eV) with an increase in film thickness from 100-700 nm, and the figure of merit revealed an increasing trend with the film thickness.

Computational Screening of Useful Hole–Electron Dopants in SnO2

“…The renormalization of the gap is nevertheless not significant enough to be detrimental for conductivity or to strongly affect the optical properties, affirming the conclusion that Ta is a suitable dopant for n-type SnO 2 . In agreement with our results, an experimental band gap of 3.78 eV upon 10% Ta doping has also been reported 55 for thin films with larger thicknesses, where bulklike properties are expected to dominate.…”