Transparent, P‐channel CuISn Thin‐film Transistor with Field Effect Mobility of 45 cm2 V–1 s–1 and Excellent Bias Stability

Abstract The p‐type semiconducting materials are essential building blocks for high performance complementary metal‐oxide semiconductor (CMOS) thin‐film transistor (TFT) circuits. Here, the development of the transparent and high performance of p‐channel copper‐iodide‐tin (CuISn) TFTs is reported. Sn alloy in CuI exhibits remarkable changes in structural and physical properties, which are studied by scanning electron microscopy, high‐resolution transmission electron microscopy, and X‐ray photoelectron spectroscopy, and Hall effect measurements. It is confirmed that 25% Sn‐alloyed CuI has p‐type conductivity with carrier concentration of 2.1 × 10 17 cm –3 and Hall mobility of 63.8 cm 2 V –1 s –1 . The TFT made with 25% CuISn exhibits the high field‐effect mobility (μ FE ) of 45.5 cm 2 V –1 s –1 , which is 10‐fold higher than that of the pristine CuI TFT. The CuISn TFT on polyimide substrate exhibits the μ FE of 42.5 cm 2 V –1 s –1 and ON/OFF current ratio of ≈10 7 . In addition, the CuISn TFT shows excellent stability with the threshold voltage shift of 0.6 V under negative gate bias stress. In addition, the hetrojunction with Li doped ZnO, CuISn/LZO p‐n junction exhibit excellent rectifying characteristics with the diode ideality factor of 1.3 and forward to reverse current ratio of ≈10 7 , which is three order higher than that of CuI/LZO diode. Therefore, the p‐channel CuISn TFTs can be widely used to open up cost‐effective transparent CMOS TFT circuits, displays, and flexible electronics.