Investigation of electrical properties of surface structures by X-Ray photoelectron spectroscopic technique under external voltage stimuli

Abstract

Electrical properties of surface structures are analyzed using XPS (X-Ray Photoelectron Spectroscopy) by means of external stimuli together with a novel technique allowing the user to record 200 conventional spectra in a period of one second with a time resolution of 5ms. Charging processes of surface structures such as SiO2 and C12-thiol-capped gold nanoclusters are monitored by time resolved XPS technique which gives an approximate charging constant of the system (RC), and electrical parameters like resistance and capacitance are estimated using external biasing and other relevant time resolved XPS data. Moreover, development and optimization of the technique are carried out by certain parameters and observing the changes in the time constants and binding energy shifts. It is also shown that application of positive and negative external bias can be used to identify two different forms of gold that exist together in the same sample, as nanoparticles and bulk metal, by means of stimulating the charging-induced-separation of the Au 4f peaks which would otherwise appear as overlapped photoemission signals in the grounded spectrum.