Carbon nanotubes based position sensors

Prototypes of individual carlbon nanotube (CNT)l based position sensors are presented on the bases of the field emission from a nanotube emitter, a telescoping (inter-layer sliding) multi-walled nanotube and a sliding nanotube on an Aui substrate. These sensors are constructed by nanomanipulation and featured by their compact sizes, simple structures, andl potential high resolutions. Field emission based one is: characterized by the non-contact configuration and suitable for an approximate sensor or as a position detector for other kinds of sensors. Telescoping motion based nanotube sensors have potentially subnanometer resolution and itlt well for a nano encoder because of their potentially quantized interlayer coupling resistance. Unidirectional and reciprocating telescopic: motions have been realized and the resistance has been found1 changing linearly with the telescoping length. The perfect linearity of the resistance of a nanotube sliding on an Au substrate promises it the highest resolution in the presented three types. However, the contact nature limits its applications.