Nanostructures on Field Effect Transistors for Methane Gas Sensing

Abstract

Field Effect Transistors (FETs) are widely investigated as gas sensing platforms due to their high sensitivity, scalability, and tunable surface chemistry. However, methane detection using FET-based sensors remains challenging due to its weak physisorption and limited charge-transfer interactions with conventional sensing materials, often resulting in relatively high detection limits. This work investigates the integration of one-dimensional transition metal trichalcogenide (TMT) nanostructures as functional sensing elements to address these limitations. This approach utilizes the high surface area to volume ratio and intrinsic anisotropy of the one-dimensional TMT nanowires, along with their spectrally dependent optical absorption properties that overlap with the near-infrared (NIR) vibrational absorption modes of methane. This spectral overlap enables enhanced coupling between methane adsorption events and the local electronic and optical responses within the sensing device. TMT nanowires were synthesized and characterized by SEM and photoluminescence (PL) spectroscopy to confirm their morphology and optical properties. Following material characterization, the nanostructures were integrated onto FET channels to form hybrid sensing devices. Electrical measurements were then conducted under controlled methane concentrations to evaluate key performance metrics, including sensitivity and concentration-dependent response behavior of the devices. These experimental results indicate that TMT-functionalized FETs exhibit enhances methane sensitivity relative to unfunctionalized or conventional FET-based sensors, consistent with a physisorption dominated sensing mechanism increased by optical coupling effects. This study demonstrates the viability of TMT nanostructures as functional materials for next generation methane sensors and highlights the potential of optically coupled TMT/FET hybrid architectures for applications in environmental monitoring, industrial safety, and extraterrestrial atmospheric analysis.