Performances of transparent indium zinc oxide thin film transistors using ZrO2 as dielectric processed by solution method

Abstract

We report here the electrical and UV‐photoelectrical performance of transparent indium zinc oxide (IZO) thin film transistors with solution‐processed zirconia (ZrO2) dielectric. The channel layers were deposited by magnetron sputter at room temperature. The ZrO2 dielectric was deposited by solution process under ambient conditions followed by low temperature annealing. The films were structurally characterized by X‐ray diffraction and atomic force microscope. Good device characteristics have been obtained with a field effect mobility of 30.7 cm2 V−1s−1, a current on/off ratio of 105, a threshold voltage of 0.8 V, and a sub‐threshold swing of 30 mV decade−1. A resistor‐load inverter was fabricated and shows reasonable transfer characteristics with a gain of about 5 at supply voltage of 2 V. It was observed that the transistors are sensitive to UV illumination. When exposed to ultraviolet light with an intensity of 120 µW cm−2, the photo‐to‐dark current ratio was more than 104 in the depletion region. All the above features make IZO thin film transistor a promising candidate to be also used as a UV‐photo transistor.