COLL 598 |
| X-ray Photoelectron Spectroscopy (XPS) is a powerful analytical technique for characterizing various chemical/physical forms of elements in 0-20 nm surface structures. It is possible to control the extent of charging and extract various analytical information by recording XPS spectra while applying external d.c. and/or pulsed voltage stimuli. The d.c. bias controls the extent of differential charging leading to total spectral separation of the XPS peaks of gold in two different physical forms (metallic gold and gold nanoclusters) present on the same surface as shown in Figure 1. We have also demonstrated that XPS data, recorded under external d.c. together with pulsed voltage stimuli, can yield valuable information related to dielectric properties of the SiO2/Si system. Another application of our method is to obtain time-resolved spectra by recording XPS spectra in different time windows after the application of a pulse. Time-resolved spectra can be used to detect, locate and quantify the charges developed in various surface structures like gold(core)/silica(shell) nanoparticles on a copper substrate.
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Surface Chemistry Symposium in Honor of Gabor Somorjai
2:00 PM-5:20 PM, Thursday, 14 September 2006 Sir Francis Drake -- Franciscan Room, Oral
Division of Colloid & Surface Chemistry |
