Hard X-ray photoelectron spectroscopy (HAXPES) (≤15 keV) at SpLine, the spanish CRG beamline at the ESRF: First results

Rubio-Zuazo, Juan1; Castro, German1; Escher, Matthias2; Merkel, Michael2; Rubio-Zuazo, Juan1; Escher, Matthias2; Castro, German R1 1France; 2Germany

First results of bulk sensitive hard X-ray photoelectron spectroscopy (HAXPES) at the Spanish CRG beamline (SpLine) at the European Synchrotron Radiation Facility (ESRF) using the HV CSA, a newly developed high energy electron analyzer, are presented.
The analyzer in use is a cylinder sector analyzer (FOCUS HV CSA) designed for energies up to 15 keV [1]. This analyzer is capable both for HAXPES and standard methods like XPS, AES and UPS. Equipped with a five-element retarding zoom lens with variable magnification (M= 1..60) and retardation (R=0.01..1500) it enables high transmission in all spectroscopy modes. It represents the first commercially available analyzer to be operated routinely up to 15 keV electron kinetic energy.
Thin Au layers deposited onto a Cu substrate have been used as a model system for bulk sensitive photoemission. The simultaneous XRD measurements give access to film thickness at exactly the same sample position.
Valence band spectra with binding energies up to 120 eV were taken for different photon energies from a 210 Å gold layer deposited onto a copper substrate. The comparison of the Cu3s and Au5s peaks show the energy dependence of the depth information. It is seen that substrate properties can be probed effectively for kinetic energies ≥ 10 keV.
The energy dependence of the effective attenuation length (EAL) for electrons in Au was determined. Core level spectra of different energies are taken for different film thicknesses. The extracted EAL of Au shows an energy dependence of (E_kin)^0.622. This is in good agreement with literature data.
[1] J.R.Rubio-Zuazo and G.R.Castro, Nucl. Instr. and Meth. A 547 (2005), 64-72

---

back