Paper TF1-FrM11
Electron Field Emission Study of Reactive Sputter Deposited Palladium Oxide Thin Films

Friday, October 19, 2007, 11:20 am, Room 602/603

Palladium oxide (PdO) is a p-type semiconductor and has many technological applications, such as catalysis, photoelectrolysis, and sensors. Because it is thermally stable up to 800°C, at which the oxide decomposes, and has a relatively low work function (3.9 eV), PdO is a suitable material for field emission applications. It has been used as the electrode material in a surface conduction electron emitter display. In this study, PdO thin films 100 nm thick were prepared on the Pt bottom electrode by reactive sputter deposition and the field emission characteristics were studied. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were used to characterize the chemical composition of the PdO thin film. Under certain deposition conditions, the PdO thin film exhibited a flake-like surface structure. The morphology of the deposited PdO thin film was highly dependent on the sputter deposition conditions, such as the gas flow ratio (Ar /O₂) and the substrate temperature. According to atomic force microscopy analysis, the PdO thin film deposited at 25°C had a root-mean-square (RMS) surface roughness of ~23 nm. The flake structure had a ridge angle smaller than 60° with a height ranging from ~30 nm to 100 nm. The sharp ridge angle can enhance the electric field at the local area around the ridge during the field emission operation. The field emission property of the PdO flake structure were studied using a simple diode configuration under a vacuum condition of ~10^-6 torr, and the turn-on field was about 8.5 V/µm at the emission current density of 10 µA/cm².