Single-Walled Carbon Nanotube Thin-Film Sensor for Ultrasensitive Gas Detection

Abstract

We demonstrated a gas sensor fabricated by growing a single-walled carbon nanotube (SWNT) thin film directly on a conventional sensor substrate. NO 2 and Cl 2 were detected down to the ppb level under room-temperature operation with a fast response. Using an electrical breakdown technique, gas response sensitivity was improved by an order of magnitude. The relationship between gas concentration and sensor response was derived based on the Langmuir adsorption isotherm, predicting a detection limit of 8 ppb for NO 2 . The SWNT thin-film gas sensor exhibits merits over other types of sensors by virtue of its simplicity in fabrication and feasible application.