Change in transport characteristics of individual multiwalled carbon nanotubes after high voltage application

Abstract

We report on the change in transport characteristics of individual multiwalled carbon nanotubes with the surface structure of the outermost layer modified through high voltage electrical breakdown. Arc-discharge synthesized MWNTs were dispersed onto an oxidized Si substrate with prepatterned reference markers. After mapping their positions, electron beam lithography was used to define electrode patterns into PMMA resist. Cr/Au electrodes were defined by thermal evaporation and lift-off. Initial I-V measurements showed Nonlinear characteristics with the total resistance decreasing from 4-5 mega ohms to a mega ohm range as the bias was increased. Sudden increase in resistance was observed as the applied voltage was further increased indicating that the outermost layer of the MWNT was modified by electrical breakdown.