A reduction process of palladium oxide thin films and hydrogen gas sensing properties of reduced palladium thin films

This study reports a novel method off abricating highly sensitive hydrogen gas sensors based on PdO thin films. The PdO thin films with a thickness of 40 nm were deposited on Si substrates under Ar and O₂ ambient conditions using a reactive dc magnetron sputtering system. Considerable changes in the resistance of the palladium oxide thin films were observed when they were initially exposed to hydrogen gas, as a result of the reduction process. The sensitivity of the PdO thin films was found to be as high as 90%. After the thin films were exposed to hydrogen gas, the nano-sized cracks were discovered to have formed on the surface of the PdO thin films. These types of nano-cracks that formed onthe deoxidized PdO thin films are known toplay a key role incausing a four-fold reduction of the response time of the absorption process. The results of this study demonstrate that deoxidized PdO thin films can be applied for use in the creation of high-sensitivity hydrogen sensors.