MWNT Sheets for Flexible Electronics
K.-H. Lee, J.H. Kim, H.-S. Jang, G.S. Lee, L. Overzet, D.E. Burk
The University of Texas at Dallas, US
Keywords: carbon nanotube sheet, transmittance, sheet resistivity
Abstract:We have pulled sheets from MWNT forests of density ~1011 cm -2 and heights of 100 um and taller. We have grown the MWNT forests in a quartz and stainless steel cylindrical chamber which has an atmospheric pressure plasma jet (APPJ) at the top. To grow the forests, we have used mixtures of helium and acetylene as the precursor. We also can use various oxidizers (O2, N2O, etc.) and reducers (NH3, H2 etc.) to assist in controlling the forest growth, amount of amorphous carbon in the growth and the ability to pull sheets from the forest. The growth is at 680 oC for 10 min on 3, 5, 7, or 10 nm iron thin films. After the sheets are pulled, 4 copper-tape electrodes are attached for a 4-point probe measurement. The length of the sheet tested here were ~8-14mm, but we have regularly made sheets many meters long from these same forests. The sheet resistivity of a single pulled sheet is ~1.5 - 3 kohm/square; and the transmittance is ~0.8 - 0.9. This latter measurement is higher by ~15% than what has been reported in the literature. This work will be important for application of CNT sheets in flexible electronics and other areas.