Extremely stretchable all-carbon-nanotube transistor on flexible and transparent substrates

The response of carbon-nanotube (CNT) transistors to large tensile strains has not been studied because of lack of stretchable devices. In this letter, we fabricate extremely stretchable single-wall CNT (SWCNT) conductive coatings on flexible and transparent elastomer substrates. We then measure the mechanical and electrical properties of the coatings and found excellent stretchability (Poisson ratio ≈ 0.31). The sheet resistances of the coatings remain largely unchanged under a large tensile strain. We then construct an active transistor on SWCNT thin films, which serve as active channel and electrodes, with polydimethylsiloxane thin film as the gate dielectric layer. The transistor exhibits excellent mechanical stability, showing no noticeable change (less than 5%) in electrical performance up to a large strain of 22.5%. The stretchable SWCNT thin-film transistor exhibits a current on–off ratio of ∼50 and field-effect mobility of ∼24 cm2 V−1 s−1, with 75% transmissivity in visible wavelength. We also found that on–off ratio increases with increased stretch strain, while mobility initially increases and then decreases with increased stretch strain.