# Layer-by-Layer Engineered Zinc–Tin Oxide/Single-Walled Carbon Nanotube (ZTO/SWNT) Hybrid Films for Thin-Film Transistor Applications

## TL;DR

Researchers developed a new hybrid material combining zinc-tin oxide and carbon nanotubes to create high-performance, indium-free transistors for flexible electronics.

## Contribution

A layer-by-layer nanocomposite strategy using SWNTs in ZTO to significantly enhance transistor performance.

## Key findings

- ZTO/SWNT thin-film transistors achieved a saturation mobility of 18.72 cm²/V·s.
- The threshold voltage was 0.84 V and subthreshold swing was 0.51 V/dec.
- Performance improved four-fold compared to pure ZTO transistors.

## Abstract

Indium-based oxide semiconductors have been commercialized because of their excellent electrical properties, but the high cost, limited availability, and environmental toxicity of indium necessitate the development of alternative materials. Among the most promising candidates, zinc–tin oxide (ZTO) is an indium-free oxide semiconductor with considerable potential, but its relatively low carrier mobility and inherent limitations in thin-film quality demand further performance enhancements. This paper proposes a new approach to overcome these challenges by incorporating single-walled carbon nanotubes (SWNTs) as conductive fillers into the ZTO matrix and using a layer-by-layer multiple coating process to construct nanocomposite thin films. As a result, ZTO/SWNTs (0.07 wt.%) thin-film transistors (TFTs) fabricated with three coating cycles exhibited a high saturation mobility of 18.72 cm2/V·s, a threshold voltage of 0.84 V, and a subthreshold swing of 0.51 V/dec. These values represent an approximately four-fold improvement in mobility compared to ZTO TFT, showing that the multiple-coating-based nanocomposite strategy can effectively overcome the fundamental limitations. This study confirms the feasibility of achieving high-performance oxide semiconductor transistors without indium, providing a sustainable pathway for next-generation flexible electronics and display technologies.