Electrothermally Induced Highly Responsive and Highly Selective Vanadium Oxide Hydrogen Sensor Based on Metal-Insulator Transition

We report highly effective hydrogen gas detection based on the metal insulator transition (MIT) by the electrothermally induced Pd-nanoparticles-decorated vanadium oxide (VO2) nanowire prepared by the efficient and size-controllable growth method originating from V2O5 thin film driven by supercooled liquid nanodroplets. By irradiating a well-defined electron beam into the nanowires, we could significantly increase the conductivity up to four times with only a modest change in the semiconductor-to-metal transition temperature (<2 degrees C). When exposed to trace amounts of hydrogen gas in a single nanowire configuration, the enhanced conductivity gave rise to about a two times as fast transition to metallic phase even near room temperature (similar to 35 degrees C), by reaching much faster (similar to 3x) a critical current density at which the self-heating initiates. Consequently, we achieved the greatly shorter response time as well as lower operating temperature and voltage for the detection of hydrogen gas in a single VO2 nanowire device, which can be attributed to the self-heating effect accelerated by the increase in the conductivity. The single nanowire sensor also shows the capability of detecting selectively hydrogen of different three gases (O-2, CO, and ethylene).