The Electron Field Emission Properties of Ag-SiO2 Nanocomposite Layers

In this work, Ag-SiO2 nanocomposite layers were synthesized by introducing Ag nanoclusters into thermally oxidised SiO2 layers, using ion implantation. The field emission (FE) properties of these layers were studied and correlated with the results from atomic force microscopy and with transmission electron microscope measurements. These nanocomposites exhibit good FE properties and give an emission current of 1 nA at electric fields as low as 13 V/μm, for a dose of 5×10Ag/cm, compared of 204 V/μm for ‘bare’ SiO2 layers. It is clearly demonstrated that the good FE properties of these nanocomposites are attributed to two types of local field enhancement mechanisms, on due to the surface morphology and the other due to electrical inhomogeneity. The isolated conductive Ag nanoclusters embedded in the electrically insulating SiO2 matrix provide a field enhancement due to the electrical inhomogeneity. Moreover, the implanted Ag ions were diffused to the surface, during the implantation process, and created a dense surface protrusion morphology at the surface, thus providing a geometric local field enhancement. The local field enhancement mechanisms in these samples are critically dependent on the implantation dose of Ag. JVSTB-AgSiO2all-VS (1).docJVSTB-AgSiO2all W.M. Tsang et al