Low-Voltage Hf-ZnO Thin Film Transistors With Ag Nanowires Gate Electrode and Their Application in Logic Circuit

Jialong Wu,Xuyong Yang,Jun Yang,Xingwei Ding

doi:10.1109/jeds.2020.2971510

Abstract

The high performance Hf doped ZnO (Hf-ZnO) flexible thin film transistors (TFTs) were fabricated using Ag NWs as gate electrode and high-k HfO2 as dielectric. The field effect mobility of Hf-ZnO is 14.7 cm2/Vs, ${I} _{\mathrm{ on}}/{I} _{\mathrm{ off}}$ ratio is more than 106, and the subthreshold swing is about 0.26 V/dec. Furthermore, after 5000 bending cycles test, the TFTs with Ag NWs still maintain a superior performance, such as the high mobility of 12.6 cm2/Vs and the small subthreshold swing of 0.33 V/dec. The operating voltage of Hf-ZnO is only 5 V, showing the great potential of application in low-powered devices. We also fabricated the resistor-loaded inverter based on the flexible TFTs. The shift of input voltage is negligible with different supplied voltages, indicating the highly-stable property of the inverter. As a result, the low consumption optoelectronics provide great inspiration for researchers to construct the next generation high performance wearable and flexible devices.

Highlights

To date, many studies have focused on the semiconductor materials for flexible substrate due to the market need for flexible displays
We systematically studied the structure, morphology, and resistance of Ag NWs
The sheet resistance of indium tin oxide (ITO) increases by nearly 300 times (R/R0) after 5000 bending cycles due to the brittle ceramic of ITO, while that of the Ag NWs increases by only 5% from 23 to 24.5 ohm/sq. after 5000 bending cycles. These results demonstrate that Ag NWs are good choose to prepare flexible devices using as an electrode

Summary

Introduction

Many studies have focused on the semiconductor materials for flexible substrate due to the market need for flexible displays. Transparent conducting electrodes have attracted considerable attention due to their low resistance and high transparency in the visible ranges [1]–[3]. Efforts ought to be made to ensure the stable performance of photonic devices working in complex environment. The indium tin oxide (ITO) is widely investigated as electrodes due to the high transparency and conductivity [4], [5]. Many drawbacks, including high-temperature processing, high cost of preparation in the vacuum system, brittleness, and sensitivity towards strain, limit its applications in flexible devices [6], [7]. ITO can be affected by oxygen and water molecules in environment [8]

Methods

Results

Conclusion