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

Abstract

Abstract 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.