Characterization of Epitaxial Ag2-xO Thin Films Grown on Sapphire
Abstract
We have grown silver oxide films with a range of stoichiometry near Ag2O by e-beam evaporation of silver in an oxygen electron cyclotron resonance (ECR) plasma. Films were deposited on r-cut sapphire substrates. A quartz crystal oscillator was used to monitor the film growth and to determine ECR oxygen flux by examining the rate of oxygen uptake on a silver film. This information was used to select the silver rate (0.1 or 1.0 å/s) and the oxygen flow rate (from 2 to 10 sccm). XRD and RHEED analysis reveals films grew with one-dimensional <111> epitaxy, true three-dimensional <002> epitaxy, or a mixed phase depending on the deposition conditions. XRD and XPS shows the composition varies with deposition conditions and can be a mixture of AgO and Ag2O. UV-vis spectroscopy shows that the films have a single absorption edge between 3.1 and 3.5 eV. Optical transmission from 500 to 700 nm is between 70 and 80%. Four-point van der Pauw conductivity and Hall effect measurements indicate that the Ag2-xO films are p-type with a conductivity on the order of 3x10-3 φ-1cm-1.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2007
- Bibcode:
- 2007APS..MARV42001R