Low‐Voltage Operable and Strain‐Insensitive Stretchable All‐Carbon Nanotube Integrated Circuits with Local Strain Suppression Layer

摘要

Abstract Stretchable devices, which can intimately contact dynamic free‐form surfaces, show great promise for wearable and implantable devices for human beings and multifunctional electronic skins for soft robotics. Although some successful stretchable devices have been reported, there are still remaining issues; in particular, the fundamental requirements for wearable devices, including low‐voltage operation, operation speed, mechanical stretchability and robustness, and easy circuit design, are needed to be satisfied simultaneously. Here, a local strain suppression layer (L‐SSL) is introduced into all‐carbon nanotube (CNT) stretchable thin‐film transistors (TFTs) and integrated circuits (ICs) to address these issues. The L‐SSL, which has a high Young's modulus, is placed on top of the active channel region to suppress the induced local strain. The resulting CNT TFTs show no drain current degradation under externally applied tensile strain of up to 35%. Furthermore, stretchable all‐CNT ICs, such as inverters and ring oscillators, can operate at low supply voltage as 0.7 V, because high‐ k material can be used underneath the L‐SSL. Biaxial stretching, an indispensable ability for wearable devices on 3D deformable surfaces such as the human body, is also achieved. The all‐CNT devices, equipped with an L‐SSL, demonstrate potential for strain‐insensitive stretchable devices with low‐voltage operation.