Sputtered highly conductive Ta-doped TiO2 transparent films

Abstract

Nd or Ta doped anatase phase TiO₂ (NTO or TTO) films, prepared via pulsed laser deposition (PLD), exhibit high electrical conductivity and visible light transmittance, indicating their potential as a cheaper alternative to replace the current widely used transparent conductive oxide Sn-doped indium oxide (ITO) films. Nevertheless, these doped TiO₂ films, particularly for TTO films, prepared by an industrial-friendly sputtering method, were widely reported to have much higher resistivity. In this work, we successfully fabricated high-quality TTO thin films on SrTiO₃ (100) substrates using a two-step sputtering process involving low-temperature deposition followed by high-temperature annealing. The resulting TTO film achieves a low resistivity of $2.57\times {10}^{-4}\mathrm{\Omega }\bullet \mathrm{cm}$$2.57\times {10}^{-4}\mathrm{\Omega }\bullet \mathrm{cm}$ and a visible light transmittance of approximately 80%. This resistivity is substantially lower than previously reported sputtered TTO films and comparable to PLD-grown TTO and NTO films. Our findings demonstrate the feasibility of producing high-quality TTO films via sputtering, paving the way for their applications in high-efficiency optoelectronic devices.