Thin film transistors using preferentially grown semiconducting single-walledcarbon nanotube networks by water-assisted plasma-enhanced chemical vapordeposition

Abstract

Nearly perfect semiconducting single-walled carbon nanotube random network thin filmtransistors were fabricated and their reproducible transport properties were investigated.The networked single-walled carbon nanotubes were directly grown by water-assistedplasma-enhanced chemical vapor deposition. Optical analysis confirmed that the nanotubeswere mostly semiconductors without clear metallic resonances in both the Raman and theUV–vis–IR spectroscopy. The transistors made by the nanotube networks whose densitywas much larger than the percolation threshold also showed no metallic paths.Estimation based on the conductance change of semiconducting nanotubes in theSWNT network due to applied gate voltage difference (conductance difference foron and off state) indicated a preferential growth of semiconducting nanotubeswith an advantage of water-assisted PECVD. The nanotube transistors showed10−5 ofon/off ratioand ∼8 cm2 V−1 s−1 of field effect mobility.