Efficient transfer of carbon nanotubes for device fabrication using an LOR resist sacrificial layer

A novel approach for transferring carbon nanotubes (CNTs) from quartz growth substrates to target substrates is presented. The fabrication of sensors based on CNTs requires the integration of nanotubes into device structures which are often not compatible with the synthesis process associated with the nanostructures. CNT transfer is an option for assembling carbon nanotubes if chemical vapor deposition (CVD) growth processes cannot be used on the device substrate, for example, due to the high synthesis temperatures. The novelty of the transfer process introduced here is the use of a thick lift-off resist (LOR, MicroChem) sacrificial layer as a transfer medium. This layer provides mechanical robustness for more convenient handling, and can be dissolved with mild chemistry resulting in only low amounts of residues on the CNTs. The process involves few and simple steps, making it a robust and efficient alternative to transfer processes with other transfer media. The successful demonstration of transistors based on transferred individual CNTs, which can e.g. serve as building blocks for nano electromechanical sensors, confirmed the suitability of the reported process for device fabrication.