Electrical characteristics of carbon nanotube network fabricated by a simple transfer method

We demonstrated a simple transfer method enables to fabricate the single-walled carbon nanotube (SWCNT) film on the plastic substrate. SWCNT network was separated from the initial substrate and transferred onto another substrate using the nitric acid. We also found that electrical conductivity of transferred film was improved. The sheet resistance of SWCNT films was changed from a 150∼300 Ω/sq to a 80∼150 Ω/sq after transferring the SWCNT film in the range of 70∼80% transmittance. This is contributed to the densification of the SWCNT network. During the transfer process, the nitric acid fills the voids between the tubes and form homogeneous interfaces among the tubes, liquid and air. Pressure differences at the interface exert bending moments to the tubes and induce deformation. By the way, deformation leads to reduce the distance between the tubes and it is stuck together due to the van der Waals forces. We suggest that this transfer method provides electrically improved SWCNT films as well as easy, contrallable and inexpensive way to fabricate. This work can open up new possibility for the flexible electronics.