X-ray photoelectron spectroscopic study on interface bonding between Pt and Zn- and O-terminated ZnO
Abstract
Interface bonding between Pt and Zn- and O-terminated ZnO surfaces was investigated by precise analysis of x-ray photoelectron spectra. The interfaces were formed by vapor depositing Pt onto the ZnO surfaces in ultrahigh vacuum.
The changes in the Zn 2p(3/2), O 1s, Zn LMM Auger, and Pt 4f(7/2) spectra upon Pt deposition were observed. The changes in the shape of the Zn LMM spectra and the shifts in the binding energy of Zn 2p(3/2) and O 1s revealed that there was a metallic Zn component in the Zn LMM and Zn 2p(3/2) spectra for Zn-terminated ZnO and a Pt-O component in the O 1s spectra for both Zn- and O-terminated ZnO.
Peaks were fitted with multiple components accordingly. The binding energy shifts of Zn 2p(3/2) and O 1s for the ZnO component were almost the same, which confirmed that the fitting was reasonable.
From the fitting results, the interface bonding was concluded to be O-terminated, i.e., Zn-O-Pt bond formation occurred at the interface for both Zn- and O-terminated ZnO. This clearly demonstrated that the stable interface bonding occurring between Pt and ZnO is Zn-O-Pt bonding whether the ZnO substrate is initially Zn-terminated or O-terminated. (C) 2013 American Vacuum Society. [http://dx.doi.org/10.1116/1.4772464]