Rearrangements of sp2/sp3 hybridized bonding with phosphorus incorporation in pulsed laser deposited semiconducting carbon films by X-ray photoelectron spectroscopic analysis

The carbon films were grown on p-type silicon substrate at room temperature by pulsed (XeCl) laser deposition technique using camphoric carbon target containing 1%, 3%, 5% and 7% of phosphorus (P) by mass. The analysis of X-ray photoelectron spectroscopy spectra of the Cls region in these films shows the presence of sp(2) and sp(3) hybridized carbon and a sp(2) satellite peak due to Tr-w* shake up. The sp(2) content is seen to remain almost constant with P content. The FWHM of the sp(2) peak increases up to 5% P but decreases for 7% P probably due to clustering of sp(2) chains and this clustering in the sp(2) phase probably decreases the band gap for the 7% P film. With P incorporation, the tetrahedral bonding configurations of the carbon network do not change appreciably, therefore, suggesting the scope of phosphorus as a potential dopant in carbon films. (c) 2006 Elsevier B.V. All rights reserved.