High mobility transparent amorphous CdO-In2O3 alloy films synthesized at room temperature

High mobility amorphous ionic oxide semiconductors (AIOSs) are ternary or quaternary heavy metal oxides which have been identified as technologically important materials for flexible transparent electronics because of their large area uniformity and low temperature processing compatibility. Here, we report on the room temperature synthesis of CdO-In2O3 alloy thin films in the full composition range using the magnetron sputtering technique on glass and plastic substrates. We found that alloys with a cation composition range of 10–55% Cd are amorphous with high mobility in the range of 30–45 cm2/Vs and an electron concentration of ∼3–4 × 1020 cm−3. The intrinsic and optical gap of these amorphous alloys varies from 2.7 to 3.2 eV and 3.2 to 3.4 eV, respectively. The room temperature processing, wide bandgap tunability, and low resistivity of ∼4–5 × 10−4 Ω cm make these amorphous films among the best AIOSs as transparent electrodes on flexible substrates.