Single carbon nanotube based infrared sensor

Abstract

As a one-dimensional nanostructural material, carbon nanotube (CNT) has been used to build different nano-electronic devices due to its unique electrical properties. In this paper, the infrared (IR) responses of individual single-wall carbon nanotube (SWNT) and SWNT film are studied. A single-wall carbon nanotube is assembled onto a pair of electrodes to form Schottky contacts. The photongenerated electron-hole pairs within the carbon nanotube are seperated by an external electric field between the two electrodes. The separated carriers contribute to the current flowing through the carbon nanotube and form photocurrent. By monitoring the photocurrent. the incident infrared can be detected and quantitated. The single-wall carbon nanotube based infrared sensor is designed and a series of efficient and reliable fabrication and assembly processes are developed for the sensor fabrication. With an atomic force microscope based nanomanipulation system as the assembly tool, a single carbon nanotube can be easily assembled onto the electrodes. Since the assembly process is controllable and reliable, it becomes possible to fabricate an individual carbon nanotubes based infrared sensor array, which was difficult to fabricate with other fabrication method. The photocurrent responses of individual SWNT IR sensor and SWNT film IR sensor are measured and analyzed. Experimental results show the good sensitivity of SWNTs to the infrared light. Our results shows a three orders higher photocurrent than the previous reported results. It has also been shown that an individual SWNT IR sensor is more sensitive than a SWNT film IR sensor.