High-mobility transistors based on nanoassembled carbon nanotube semiconducting layer and SiO2 nanoparticle dielectric layer

The authors report the fabrication and characterization of high-mobility thin-film transistors (TFTs) using layer-by-layer (LBL) nano self-assembled single-walled carbon nanotubes (SWCNTs) as the semiconducting material and SiO2 nanoparticles as the gate dielectric material. The channel length and the effective thickness of the SWCNT semiconductor layer are 50 mu m and 38 nm, respectively. The effective thickness of the SiO2 dielectric layer is 180 nm. The SWCNT TFT exhibits p-type semiconductor characteristics and operates in the accumulation mode, with a hole mobility (mu(p)) of 168.5 cm(2)/V s, a normalized transconductance (g(m)/W) of 0.5 S/m, a threshold voltage (V-th) of -3 V, and an on/off current ratio (I-on/off) of 4.2. The combination technique with LBL nano self-assembly and microlithography provides a simple, low-temperature, and highly efficient approach to fabricate inexpensive TFT devices. (c) 2006 American Institute of Physics.