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

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 cm 2 V −1 s −1 and high on/off current ratio of~10 7 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.

Engineering Copper Iodide (CuI) for Multifunctional p‐Type Transparent Semiconductors and Conductors

“…[ 37 , 38 ] Owing to these features, CuI has been widely used in heterojunction diodes, thermoelectric devices, photodetectors, and as TCs and hole‐transport layers in photovoltaic devices and transistors ( Figure 1 ). [ 35 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 ]…”

8‐5: Invited Paper: P‐Type Oxide Semiconductors for Displays: Material Design and Field‐Effect Devices

“…However, CuI also suffers from issues including solution processability, instability, a high density of defects etc. [17,20].…”

“…Other emerging devices: As a consequence of the limitation of p-type oxide materials, p-type semiconductors other than oxides are also proposed to make p-channel TFTs and CMOS devices, including CuI [20,35,36], CuSCN [37], and chalcogenides [38]. CuI is a rising star among non-oxide choices due to its high mobility, ease of fabrication and better compatibility with oxide thin films.…”

“…Zn doped CuI TFT achieved an exciting μEF over 5 cm 2 /Vs and on/off ratios of ~107 through spincoating at 80 o C[20]. Further integration of CMOS inverter together with a-IGZO TFT exhibit excellent gain value of 56.…”

8‐4: Invited Paper: Transparent Zn Doped‐CuI for High‐Performance p‐Channel Thin Film Transistors

“…However, despite the extensive studies, an 'ideal' p-type semiconductor satisfying the industrial requirements of high mobility and optical transmittance has not been fabricated. Although CuI has recently attracted considerable interest 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 [2][3][4].…”