Weak backscattering in deflected doped carbon nanotubes.

Carbon nanotubes (CNTs) are highly sensitive towards dipole molecules, mechanical loads, interfacial contacts, chemical modifications and temperature fluctuations. Their applications are currently limited to electron-field-emission and gas-sensing devices. In fact, CNTs can also be used as strain-sensing elements; for example, variations in CNT resistance with bending strain have been characterized by deflecting nanotubes using an AFM tip. Tombler et al. discovered that, when deflected, nanotubes reach 148, and their corresponding conductance reduces significantly as a result of temporary sp bonding. A similar phenomenon was observed by Paulson et al. Firstly, the CNT resistance increases considerably with tip-force application due to a tube movement with respect to the electrodes. Secondly, the tube resistance does not change with a small bending strain; it becomes immeasurable when the tube fractures. These examples, however, point to the fact that nanotube resistance increases with lattice distortions. We found that p-doped CNTs behave differently when subjected to bending. Constant bending of doped CNTs is accompanied by an indistinctive change of the tube resistance.