Determination of the Cu2O Thickness on BTAH-Inhibited Copper by Reconstruction of Auger Electron Spectra

The influence of the benzotriazole (BTAH) inhibitor on the thickness of the Cu2O oxide layer formed on Cu immersed in 3% NaCl solution was studied with angle-resolved X-ray photoelectron spectroscopy. The X-ray-induced Auger Cu L3M4,5M4,5 spectra were reconstructed with the Monte Carlo algorithm using the spectra of the basic constituents [Cu(I)BTA, Cu2O, and Cu] formed on the surface. The relative contributions of the basic constituents to the composite Cu L3M4,5M4,5 spectra measured at different emission angles were then used to estimate the thickness of the Cu2O oxide layer. The results show that the presence of BTAH substantially reduces the thickness of the Cu2O oxide layer formed on Cu in chloride media. The average thickness of the Cu2O layer below the Cu(I)BTA layer is estimated to be 1.3 +/- 0.2 nm, whereas the Cu2O thickness of the noninhibited sample is 2.2 +/- 0.3 nm. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3463718] All rights reserved.