Carbon nanotube thin film transistors on flexible substrates

Abstract

Carbon nanotube thin film transistors (CNT-TFTs) are fabricated on flexible substrates using purified, surfactant-based CNT suspensions, with >95% semiconducting CNT fraction. The TFTs are made up of local bottom-gated structures with aluminum oxide as the gate dielectric. The devices exhibit high ON current densities (0.1 μA/μm) and on-off ratios (∼105) with mobility values ranging from 10-35 cm2/Vs. A detailed numerical model is used to understand the TFT performance and its dependence on device parameters such as TFT channel length, CNT density, and purity.

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

“…19,22,28 In other reports, a brittle oxide layer is used as a dielectric insulator, but the insulating function of this material is not guaranteed under a strain greater than 5%. [19][20][21][24][25][26] All-CNT transistors may be used to overcome these disadvantages. Previous studies investigated all-CNT transistors.…”

“…[6][7][8][9][10][11][17][18][19][20][21][22][23][24][25][26][27][28][29] Flexibility of these transistors are measured by bending flexible substrates that are plastic and cannot be stretched. 18,20,21 In some studies, source, drain, or gate electrodes behaved as metallic materials; therefore, they cannot be stretched.…”

Multifunctional nanocomposites reinforced with carbon nanopapers

“…One of the most commonly used materials for S/D/G electrodes is thin paper of metals because they have been experimentally demonstrated to have reasonably high flexibility and durability (Cao et al, 2008;Kang et al, 2007;Chimot et al, 2007;Tseng and Tai, 2009;Wang et al, 2012;Chandra et al, 2011;Cao et al, 2006b). Wang et al (2012) used high work function metal with a thin layer of Ti metal as the S/D/G electrodes and were electrically stable on devices up to a radius of 1.27 mm, as shown in Figure 15.7(a) and (b).…”

“…Depending on the chirality along the graphene sheet, either semiconducting or metallic electronic states are created (Saito et al, 1992b). CNTs and graphene are ideal candidates for use in device areas such as transistors (Kang et al, 2007;Chimot et al, 2007;Tseng and Tai, 2009;Wang et al, 2012;Chandra et al, 2011;Cao et al, 2006b;Ishikawa et al, 2008;Ryu et al, 2008;Liang et al, 2009;Derycke et al, 2001;Hur et al, 2005b), flexible displays, and transparent electrodes (Parikh et al, 2006;Hu et al, 2009a). Although devices composed of individual CNTs and graphene have been considered as an option to enable some of these applications, they have been deemed impractical for commercialization because of the difficulty in placing individual CNTs at desired locations and the variability of their electrical properties depending on the chirality and diameters of the CNTs.…”

Random networks of carbon nanotubes optimized for transistor mass-production: searching for ultimate performance

“…Carbon nanotube thin-film transistors are expected to enable the fabrication of high-performance, flexible and transparent devices using relatively simple techniques [4,5,6,7,8,9,10,11]. As-grown networks of single-walled carbon nanotubes (CNTs) contain both metallic (m-CNTs) and semiconducting (s-CNTs) nanotubes, which leads to a trade-off between on-conductance and on/off conductance ratio [12,13,14].…”