Electron beam induced carbonaceous deposition as a local dielectric for CNT circuits

Abstract

Evaluating the electrical nature of carbon nanotubes (CNTs) from a collection requires establishing electrical contacts across individual CNTs lying on a dielectric layer. In this work, it is shown how a dielectric layer may be inserted underneath a chosen CNT. This has been accomplished by the electron beam induced carbonaceous deposition process in the presence of moisture and residual hydrocarbons present in the SEM chamber. When performed at a CNT location on a Si substrate, the CNT instead of getting buried underneath is found to be lifted on top of the carbonaceous platform, as if due to nonwetting nature of CNT surface. By fixing one end of the CNT on the Ag/Si substrate using a Pt deposit and lifting rest of the length to lie on a carbonaceous platform, the I–V data from nanotubes of varying resistances have been collected using conducting AFM. The chosen nanotubes have also been examined by Raman measurements. The method is particularly useful while working with a random collection of nanotubes resulting from a chemical process.