Effect of Mg doping on the hydrogen-sensing characteristics of ZnO thin films

Undoped ZnO and Mg0.1Zn0.9O films, both with good crystalline quality and smooth surface, were grown on c-cut sapphire by pulsed laser deposition (PLD) technique. Hydrogen-sensing measurements indicated that the MZO film showed much higher H2 sensing performance than the undoped ZnO film did. The sensor response is 2.9 for undoped ZnO film to 5000 ppm H2 at 300 °C. The gas response increased to about 50 for the MZO film measured under the same condition. To understand the enhancement of the sensing performances of the MZO film, the gas sensing mechanism of the films was proposed and discussed.