摘要
The gap closing mechanism in nanostructured hydrogen sensors is promising for the detection of small gas streams, but so far it has been challenging due to the difficulty in fabrication. We demonstrate here the simple preparation of the self-assembled network of palladium islands on MgO(001) substrate that can be used to explore this mechanism, using the DC magnetron sputtering technique. Pd films of 100 nm in thickness, deposited at 550 °C, possess the (002) preferred orientation that it still retains while doping with rare-earth metals such as Gd or Tb. However, the grain size and surface morphology of the Pd films change markedly with the addition of dopants, offering a route for tailoring the film toward higher sensitivity and scalable responses to changes in H 2 concentrations. All the sensors show the decreased resistance in the presence of H 2 , the behavior attributed to the physical gap closing mechanism. Sensing performances of Pd films without doping and those of doped samples are also compared.