ZrO2-TiO2 thin films: a new material system for mid-infrared integrated photonics

Mid-infrared (MIR, 2 6 μm wavelength) transparent metal oxides are attractive materials for planar integrated MIR photonic devices and sensing applications. In this report, we present reactive sputtering deposited ZrO2-TiO2 (ZTO) thin films as a new material candidate for integrated MIR photonics. The material structure and optical properties were systematically studied as a function of Ti concentration. The thin film index of refraction monotonically increases with Ti concentration, while the film crystallinity decreases. Fully amorphous ZTO films were achieved with 40 at.% Ti doping on various substrates. 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