Electrical and thermal insulation via an oxidized, rough contact interface for the electro-thermal actuation of carbon nanotubes

Two separated silicon structures in the shape of a hook and a T-bar are patterned by the Bosch process, and connected to a suspended carbon nanotube and an electro-thermal actuator, respectively. The contact interface between these two structures can provide electrical and thermal insulation when the nanotube is strained by the actuator. The rough etched silicon side walls significantly reduce physical contact area, resulting in a point-contact-like thermal conductance of 105 nW/K. A simulation result indicates that, when the temperature of the T-bar (actuator side) is increased by 191 K, the increased temperature of the hook (nanotube side) is less than 2.5 K. Using the native oxide on the silicon surfaces and symmetrically biasing the actuator, the nanotube is electrically insulated from the actuator. In addition, the gap between the T-bar and the hook can buffer the stress-induced mechanical deformation of the actuator during release so that the suspended nanotube will not be over-strained or damaged. Reproducible transport measurements of strained suspended nanotubes are demonstrated. Hence, this device architecture avoids rupture of the nanotube during release. Moreover, it also prevents the nanotube from being electrically or thermally coupled with the actuator during measurements.