X-ray Photoelectron Spectroscopy in the Analysis of Titanium and Palladium Nanolayers

Abstract

In the presented study, X-ray photoelectron spectroscopy and total reflection X-ray photoelectron spectroscopy methods were applied to analyze the Ti (75 nm) and Pd (100 nm) nanolayers deposited on the Si substrate using magnetron sputtering. The aim of the research was to determine the elemental composition and surface homogeneity of the analyzed nanolayers before their irradiation with highly charged xenon ions and to estimate the detection limit of the X-ray photoelectron spectroscopy technique for various glancing angles. The measurements were conducted using the SPECS mono-XPS system in the Institute of Physics at the Jan Kochanowski University (Kielce, Poland). The experimental setup and measurement conditions for the studied Ti and Pd layers are described. The X-ray photoelectron spectroscopy spectra were registered both for the non-total (35° and 10° angles) and total reflection (2.2° for the Pd nanolayer  and  1.5° for the Ti nanolayer) regimes. The position of  the  C 1s  photoelectron  peak was applied (C–C component, binding energy 284.8 eV) to calibrate energy. First, the homogeneity of the nanolayers was investigated. The analysis of spectra concentrated on investigating the photoelectron peaks and, consequently, on determining the following: the binding energy of electrons, the intensity and full width at half maximum of photoelectron peaks, the background level, and the elemental composition of the nanolayer surface. In this study, the detection limit of the X-ray photoelectron spectroscopy measurements for different photoelectron peaks was calculated in relation to the excitation angle. An improvement of the X-ray photoelectron spectroscopy detection limit by a factor of 3–6, depending on the type of photoelectron peak, was observed for the angles below the critical angle of the X-ray total reflection phenomenon.