The electronic and optical properties of Cu, CuO and Cu(2)O were studied by x-ray photoelectron spectroscopy (XPS) and reflection electron energy-loss spectroscopy (REELS). We report detailed Cu 2p, Cu LVV, O 1s and O KLL spectra which are in good agreement with previous results. REELS spectra, recorded for primary energies in the range from 150 to 2000 eV, were corrected for multiple inelastically scattered electrons to determine the effective inelastic scattering cross section. The dielectric functions and optical properties were determined by comparing the experimental inelastic electron scattering cross section with a simulated cross section calculated within the semi-classical dielectric response model in which the only input is Im(-1/ε) by using the QUEELS-ε(k,ω)-REELS software package. By Kramers-Kronig transformation of the determined Im(-1/ε), the real and imaginary parts (ε(1) and ε(2)) of the dielectric function, and the refractive index n and extinction coefficient k were determined for Cu, CuO, and Cu(2)O in the 0-100 eV energy range. Observed differences between Cu, CuO and Cu(2)O are mainly due to modifications of the 3d and O 2p electron configurations.

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We have determined the electronic and optical properties of six polymers: Polymethylmethacrylate (PMMA), polyethylene (PE), polyvinyl chloride (PVC), polyester (PET), polypyrrole (PPY), and polyamide (PA6) for energy losses from 0 to 70 eV by analysis of reflection electron energy-loss spectroscopy (REELS) spectra. We found that the surface was easily damaged by the incident electron beam, in particular for energies above 500 eV. The damage results in new peaks in the bandgap region and the polymers become metallic. Great care was exerted to determine experimental conditions under which these effects are minimized. The REELS spectra were corrected for multiple inelastically scattered electrons with the QUASES-XS-REELS software to determine the effective inelastic-scattering cross sections. From these cross sections, we found that the band gaps for PMMA, PE, PVC, PET, PPY, and PA6 are 5.0 eV, 7.5 eV, 7.0 eV, 3.0 eV, 3.5 eV, and 5.1 eV, respectively. Quantitative analysis of the experimental cross sections was carried out by using the QUEELS-e(k,x)-REELS software to determine the dielectric function and optical properties. This is done by comparing the experimental REELS inelastic electron-scattering cross-section with a simulated cross section in which the only input is Im(À1=e). The dielectric function is expressed as a sum of oscillators and the oscillator parameters are determined. Good agreement between the experimental and theoretical cross section is achieved for all polymers. From Im(À1=e), the real and imaginary parts of e (x), the refractive index, and the extinction coefficient were determined for all polymers in the energy range hx ¼ 0 to 70 eV. An oscillator is clearly observed for PPY, PET, and PA6 at $ 6.7 eV, which corresponds to the p plasmon. This oscillator is not found for PMMA, PE, and PVC. A set of oscillators in the 20-30 eV energy range corresponding to the rþp plasmon is found for all polymers. V C 2012 American Institute of Physics.

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The electronic and optical properties of Al 2 O 3 /SiO 2 dielectric thin films grown on Si(1 0 0) by the atomic layer deposition method were studied by means of x-ray photoelectron spectroscopy and reflection electron energy loss spectroscopy (REELS). The band gaps of the Al 2 O 3 /SiO 2 thin films before annealing and after annealing were 6.5 eV and 7.5 eV, respectively, and those of the γ-Al 2 O 3 and α-Al 2 O 3 phases were 7.1 eV and 8.4 eV, respectively. All of these were estimated from the onset values of the REELS spectra. The dielectric functions were determined by comparing the effective cross-section determined from experimental REELS with a rigorous model calculation based on dielectric response theory, using available software packages. The determined energy loss function obtained from the Al 2 O 3 /SiO 2 thin films before annealing showed a broad peak at 22.7 eV, which moved to the γ-Al 2 O 3 position at 24.3 eV after annealing. The optical properties were determined from the dielectric function. The optical properties of the Al 2 O 3 /SiO 2 thin films after annealing were in good agreement with those of γ-Al 2 O 3. The changes in band gap, electronic and optical properties of the Al 2 O 3 /SiO 2 thin films after annealing indicated a phase transition from an amorphous phase to the γ-Al 2 O 3 phase after annealing.