Functionalized Carbon-Nanotubes-Based Thin-Film Transistor Sensor for Highly Selective Detection of Methane at Room Temperature

Gas sensors based on carbon nanotubes (CNTs) as channel materials have been widely considered as promising candidates for the detection of toxic gas. However, effectively detecting methane (CH4) with CNTs-based sensors remains challenging because nonpolar CH4 molecules find it difficult to directly interact with CNTs. Herein, a functionalized CNTs-based thin-film transistor (TFT) sensor is proposed for the highly effective detection of CH4 at room temperature, where CNTs with high semiconductor purity are used as the main TFT channel. The VO2 and Pd nanoparticles serve as surface-active agents to modify the CNTs, and the surface-modified CNTs-based gas sensor exhibits excellent gas-sensing properties for the detection of CH4. In particular, the Pd@VO2 composite-modified CNTs-based TFT sensor has excellent sensitivity to CH4 in the detection range of 50 to 500 ppm. The detection limit is as low as 50 ppm, and the sensor exhibits excellent selectivity and superior repeatability. The improved gas-sensing properties of the CNTs-based gas sensor is primarily attributed to the modification of the sensitive channel that can promote the electronic interaction between CH4 and gas-sensing materials. This study provides guidance for the development of high-performance CH4 sensors operating at room temperature.