[Abstract]

Advancement of transparent electronics is limited by the lack of stablewide-bandgap p-type semiconductors. Although copper iodide (CuI) showspotential in transparent p-type thin-film transistors (TFTs), controlling carrierconcentration and chemical stability remains challenging. Here, it isdemonstrated that cadmium (Cd) doping effectively suppresses holeconcentration and enhances the air stability of CuI thin films. Theincorporation of chemically soft Cd2+ ions improve environmental robustness,enabling conventional photolithography under ambient conditions. Optimized4.0% Cd-doped CuI TFT exhibits a saturation mobility of 5.58 ± 0.71 cm2 V−1s−1 , an I on /I off ratio of 10 7 , and improved negative bias stability (????Vth = 1.9 Vat 2 MV cm−1 for 3600 s). Furthermore, a 7-stage ring oscillator using CuI:Cdfilm patterned via standard photolithography in air exhibits an operatingfrequency of 138.38 kHz with a propagation delay of 7.66 µs at a ????-ratio of 5:1,highlighting its potential for industrial application of transparent electronics