24 research outputs found
Controlled Growth, Patterning and Placement of Carbon Nanotube Thin Films
Controlled growth, patterning and placement of carbon nanotube (CNT) thin
films for electronic applications are demonstrated. The density of CNT films is
controlled by optimizing the feed gas composition as well as the concentration
of growth catalyst in a chemical vapor deposition process. Densities of CNTs
ranging from 0.02 CNTs/{\mu}m^2 to 1.29 CNTs/{\mu}m^2 are obtained. The
resulting pristine CNT thin films are then successfully patterned using either
pre-growth or post-growth techniques. By developing a layered photoresist
process that is compatible with ferric nitrate catalyst, significant
improvements over popular pre-growth patterning methods are obtained.
Limitations of traditional post-growth patterning methods are circumvented by
selective transfer printing of CNTs with either thermoplastic or metallic
stamps. Resulting as-grown patterns of CNT thin films have edge roughness (< 1
{\mu}m) and resolution (< 5 {\mu}m) comparable to standard photolithography.
Bottom gate CNT thin film devices are fabricated with field-effect mobilities
up to 20 cm^2/Vs and on/off ratios of the order of 10^3. The patterning and
transfer printing methods discussed here have a potential to be generalized to
include other nanomaterials in new device configurations