[Abstract]

Transparent semiconductors are in demand for the development of flexible and large-area displays. Copper iodide is a promising p-type semiconductor with high optical transparency and electrical conductivity, where suitable zinc doping can effectively tune the carrier concentration for high-performance thin film transistors. This study proposes a CuI/Zn-doped CuI heterojunction structure for p-type metal halide TFTs. The industry-compatible vapor-deposited heterojunction structure composed of CuI/Zn-doped CuI TFTs offers effective hole transport and a reasonable off-state current through the low conductive Zn-doped CuI channel layer and efficient carrier supply from the highly conductive CuI upper layer. The optimized heterojunction p-type TFTs exhibited a linear field-effect mobility of ∼5 cm2 V−1 s−1 and on/off current ratio of ∼106. This novel heterojunction structure of metal halide TFTs offers a promising pathway for the development of next-generation transparent electronics and displays, incorporating possible vertical-stack integrations and complementary circuits with n-type metal oxide semiconductors.