Development of Highly Sensitive Ethane Gas Sensor Based on 3D WO₃ Nanocone Structure Integrated with Low‐Powered In‐Plane Microheater and Temperature Sensor

Abstract Metal oxide nanostructures are the most promising materials for the fabrication of advanced gas sensors over two decades. Especially, reliable responsivity and selectivity for various harmful gases are the main requirements for the future chemiresistive‐type gas sensors. Here, a 3D nanocone (NC) of WO₃ for a real‐time ethane (C₂H₆) gas sensor is reported. A compact WO₃ nanoparticles thin film deposited on the sensor interdigitate electrodes (IDEs) by using radio frequency (RF) sputter and subsequently, WO₃ thin film is converted into highly ordered 3D NC with simple monolayer of polystyrene. An in‐plane microheater integrated with a temperature sensor is also developed here in which the heater, temperature sensor, and the gas sensor share the same plane instead of a conventional vertical structure where the microheater and the sensor IDE are placed one above the other. Prior to the fabrication, COMSOL simulations are carried away to predict the heater performance and surface charge densities of the NC structures. A comparative study between the planar WO₃ and highly ordered 3D NC WO₃ in sensor response has been conducted. The fabricated sensors (planar WO₃) and 3D NC WO₃ show a high response ΔR/R (%) of 44% and 52% to 100 ppm of ethane at 200 °C respectively.