Design Criteria for Transparent Single-Wall Carbon Nanotube Thin-Film Transistors

Abstract

A study based on two-dimensional percolation theory yielding quantitative parameters for optimum connectivity of transparent single-wall carbon nanotube (SWNT) thin films is reported. Optimum SWNT concentration in the filtrated solution was found to be 0.1 mg/L with a volume of 30 mL. Such parameters lead to SWNT fractions in the films of approximately Phi = 1.8 x 10(-3), much below the metallic percolation threshold, which is found to be approximately PhiC = 5.5 x 10(-3). Therefore, the performance of transparent carbon nanotube thin-film transistors is limited by the metallic SWNTs, even below their percolation threshold. We show how this effect is related to hopping or tunneling between neighboring metallic tubes.

Phonon contribution to electrical resistance of acceptor-doped single-wall carbon nanotubes assembled into transparent films

“…Transparent conducting netlike single-wall carbon nanotube (SWCNT) films are promising candidates for the production of transparent electrodes for photovoltaic devices, displays, and other optoelectronic applications [1][2][3][4][5][6][7][8][9]. The conducting framework of such electrodes consists of a SWCNT network with metallic (M) and semiconducting (S) nanotubes [10,11] in the approximate ratio of 1:2 [12].…”

“…For practical application, industry specification for transparent conducting films requires transparencies higher than 90% and sheet resistance R sq lower than 90 ohm/sq (see, e.g., [13]). The highly transparent (80-90%) SWCNT films formed from pristine nanotubes with noticed M/S ratio have the values of R sq ranging from unacceptable values (10 3 -10 4 ohm/sq) [2,8] to those (89-310 ohm/sq) [4,[14][15][16] which are in close proximity to required ones. The sheet resistance of pristine SWCNT films depends on the purity of the samples, the length and diameter of the nanotubes, and the size of the SWCNT bundles [13,15].…”

Charge Transport in Interpenetrating Networks of Semiconducting and Metallic Carbon Nanotubes

“…Thin (submonolayer) CNT films have been demonstrated as a material for low cost flexible transparent field effect transistors (FETs), [1][2][3][4][5][6][7] as well as for gas, pH, chemical, DNA, and optical/IR sensors. [8][9][10][11] The best CNTN-FETs to date have reached high ON/OFF ratios around 10 5 while at the same time achieving field effect mobilities on the order of 10 cm .…”

Performance-determining factors in flexible transparent conducting single-wall carbon nanotube film

“…The FE-SEM images of SWCNTcoated TCFs according to dipping treatment number show that the number of intersection points increases significantly with the number of dippings. The percolation threshold should reach a minimum amount of SWCNT deposits to maximize optical transmittance [18][19][20]. dipping times and then decreases at 300 dipping times.…”