Improvement of Piezoresistive Properties of Suspended Single‐Walled Carbon Nanotube Arrays via Selective Trimming

An efficient procedure for the fabrication of highly force-sensitive aligned and suspended primitive single-walled carbon nanotube (SWNT) devices is developed. First, an array of individual ultra-long SWNTs is grown by chemical vapor deposition and suspended between two adjacent Au electrodes adhered on a breakable Si wafer. Armchair metallic SWNTs and low-resistivity quasi-metallic SWNTs are then selectively removed from the suspended SWNT array to upgrade the electromechanical mechanism of this type of sensitive device by strain-based electrical burn-off. Second, energy band and thermoelectronic emission theories in semiconductor physics are combined to calculate and analyze the effect of the length of the suspended SWNT on the aforementioned burn-off method. The increase in length of the suspended SWNT section facilitates the easy electromechanical characteristic optimization of the suspended SWNT array. Moreover, the suspended SWNT array has a strong electromechanical response after strain-based electrical burn-off with sensitivity (gauge factor) of more than 600, linearity of less than 8.27%, and no hysteresis. Finally, the thermal effect is discussed in terms of this analytical method and experimental results.