Intrinsically stretchable all-carbon-nanotube transistors with styrene-ethylene-butylene-styrene as gate dielectrics integrated by photolithography-based process.

Min Zhang,Weihong Huang,Ziwei Zhang,Haoxuan Jiao,Chunhui Du,Qiuyue Huang

doi:10.1039/c9ra10534d

Abstract

In recent years, stretchable electronics have attracted great attention because of their broad application prospects such as in the field of wearable electronics, skin-like electronics, medical transplantation and human–machine interaction. Intrinsically stretchable transistors have advantages in many aspects. However, integration of intrinsically stretchable layers to achieve stretchable transistors is still challenging. In this work, we combine the excellent electrical and mechanical properties of carbon nanotubes with excellent dielectric and mechanical properties of styrene–ethylene–butylene–styrene (SEBS) to realize intrinsically stretchable thin film transistors (TFTs). This is the first time that all the intrinsically stretchable components have been combined to realize multiple stretchable TFTs in a batch by photolithography-based process. In this process, a plasma resistant layer has been introduced to protect the SEBS dielectric from being damaged during the etching process so that the integration can be achieved. The highly stretchable transistors show a high carrier mobility of up to 10.45 cm2 V−1 s−1. The mobility maintains 2.01 cm2 V−1 s−1 even after the transistors are stretched by over 50% for more than 500 times. Moreover, the transistors have been scaled to channel length and width of 56 μm and 20 μm, respectively, which have a higher integration level. The stretchable transistors have light transmittance of up to 60% in the visible range. The proposed method provides an optional solution to large-scale integration for stretchable electronics.

Highlights

Stretchable electronics have drawn lots of attention for their broad applications such as in wearable electronics, skin-like electronics,[1] medical transplantation and human–machine interfaces
Bao et al fabricated intrinsically stretchable and scalable transistor arrays with the device density of 347 transistors per square centimeter.[1]. These efforts improved the performance of the stretchable transistors, and proposed many novel processing methods to fabricate stretchable electronics such as printing, transferring, dip-coating etc
Finding a way to fabricate transistors with high stretchability, high electrical performance, small feature size, and potential for mass production at the same time is vital to the development of stretchable transistors

Summary

Introduction

Stretchable electronics have drawn lots of attention for their broad applications such as in wearable electronics, skin-like electronics,[1] medical transplantation and human–machine interfaces. Finding a way to fabricate transistors with high stretchability, high electrical performance, small feature size, and potential for mass production at the same time is vital to the development of stretchable transistors To achieve this target, the traditional process based on photolithography and plasma etching has many advantages on process compatibility, equipment maturity, and low cost. Zhang et al fabricated ultralow-voltage exible all-carbon transistors with carbon nanotubes as channel and electrodes, and graphene oxide as gate dielectric These transistors showed high carrier mobility up to 105 cm[2] VÀ1 sÀ1, extraordinary subthreshold swing of 170 mV decÀ1, a low threshold voltage of À0.3 V, and a small bending radius of 1 mm.[7] stretchable allcarbon transistors have not been reported before due to the obstacles during process integration. The transistors have a length and width of 20 mm and 56 mm, respectively, which have smaller area than most of the reported stretchable organic and CNT transistors, indicating its advantages for high-level integration

Fabrication of stretchable transistors

Physical characterization of intrinsically stretchable transistors

Electrical and mechanical characterization

Transparency characterization

Comparison of intrinsically stretchable transistors