High-performance p-channel transistors with transparent Zn doped-CuI

Huihui Zhu,Se-Jun Kim,Ao Liu,Won-Tae Park,Hyungjun Kim,Yong-Young Noh,Myung-Gil Kim

doi:10.1038/s41467-020-18006-6

Abstract

‘Ideal’ transparent p-type semiconductors are required for the integration of high-performance thin-film transistors (TFTs) and circuits. Although CuI has recently attracted attention owing to its excellent opto-electrical properties, solution processability, and low-temperature synthesis, the uncontrolled copper vacancy generation and subsequent excessive hole doping hinder its use as a semiconductor material in TFT devices. In this study, we propose a doping approach through soft chemical solution process and transparent p-type Zn-doped CuI semiconductor for high-performance TFTs and circuits. The optimised TFTs annealed at 80 °C exhibit a high hole mobility of over 5 cm2 V−1 s−1 and high on/off current ratio of ~107 with good operational stability and reproducibility. The CuI:Zn semiconductors show intrinsic advantages for next-generation TFT applications and wider applications in optoelectronics and energy conversion/storage devices. This study paves the way for the realisation of transparent, flexible, and large-area integrated circuits combined with n-type metal-oxide semiconductor.

Highlights

‘Ideal’ transparent p-type semiconductors are required for the integration of high-performance thin-film transistors (TFTs) and circuits
Its valence band maximum (VBM) is characterised as a hybridisation of Cu 3d and I 5p states, while the conduction band minimum (CBM) is characterised as Cu 4s states (Supplementary Fig. 1a)
Similar trends were observed for dopings of Pb2+ and Bi3+ at Cu+ sites (Supplementary Fig. 1b, c), except that the mid-states of the Bi3+-doped system were considerably closer to the Fermi level, far away from the CBM

Summary

Introduction

‘Ideal’ transparent p-type semiconductors are required for the integration of high-performance thin-film transistors (TFTs) and circuits. CuI has recently attracted attention owing to its excellent opto-electrical properties, solution processability, and low-temperature synthesis, the uncontrolled copper vacancy generation and subsequent excessive hole doping hinder its use as a semiconductor material in TFT devices. We propose a doping approach through soft chemical solution process and transparent p-type Zn-doped CuI semiconductor for high-performance TFTs and circuits. Considering the industrial requirements of high mobility and optical transmittance, despite the extensive studies, the reported p-type metal-oxide semiconductors still exhibit insufficient performance[5]. To reduce the number of holes for the realisation of a high-performance CuI-based TFT, a feasible approach is to create donor-like iodine vacancies by thermally decomposing the lattice iodine, as demonstrated in our recent study[20]. The further integration of logic inverter with a a-IGZO TFT exhibits excellent performance with a high gain of 56

Methods

Results

Conclusion