Volume 22, Issue 1, June 2015
Index of content:
Transition Metal Manganites Prepared by a Green and Low-Temperature Wet Chemistry Route, Investigated by XPS22(2015); http://dx.doi.org/10.1116/11.20141103View Description Hide Description
In the present contribution, three transition metal manganites, namely the copper manganite CuMnO2 and the zinc manganites ZnMnO3 and ZnMn2O4, were investigated through X-ray photoelectron spectroscopy (XPS). The chosen synthesis route involved the combination of coprecipitation of oxalates from an aqueous solution and hydrothermal processing at a mild temperature (180 °C). The precipitates were then separated and dried for 4 h at 80 °C, yielding crystalline nanostructured powders without the need for calcination. Along with survey scans of the analyzed samples, detailed spectra of the C 1s, O1s, Mn 2p, Mn 3p, Mn LMM as well as Cu 2p, Cu 3p, Cu LMM, Zn 2p and Zn LMM (depending on the sample in question) were collected. The data obtained from these analyses is discussed.
22(2015); http://dx.doi.org/10.1116/11.20141101View Description Hide Description
Calcium oxalate monohydrate is found as a by-product of environmental damage to stonework of importance in preserving cultural heritage. XPS (X-ray Photoelectron Spectroscopy) was here used to characterize the standard compound, calcium oxalate monohydrate, RPE, chemically synthesized as provided by Carlo Erba Reagents - Cod. 434004. Degradation occurred during analysis and this is described. Repeat XPS acquisitions have allowed us to monitor the spectral changes of calcium oxalate during the whole process of analysis: its degradation was rationalized by considering the effect of x-ray power; UHV exposure; and thermal effects suffered by the powdered sample after its insertion into the spectrometer and, particularly, during spectra acquisition. Measurement of degradation with time enabled extrapolation to yield the primary composition. It was found that samples will completely dehydrate in ultra high vacuum, UHV. Although dehydrated samples are then stable in UHV, during XPS acquisitions degradation of calcium oxalate occurs and continues in UHV, even in the absence of x-ray exposure.
Analysis of Silicon Germanium Standards for the Quantification of SiGe Microelectronic Devices Using AES22(2015); http://dx.doi.org/10.1116/11.20141102View Description Hide Description
Four samples of well-defined silicon-germanium alloys were used as standards for calibration purposes to allow accurate quantification of silicon-germanium-on-insulator (SGOI) microelectronic devices using Auger electron spectroscopy. Narrow Si KLL and the Ge LMM, high resolution Si KL2,3L2,3 and Ge L3M4,5M4,5 together with survey spectra were collected and are presented from each sample. A matrix effect was observed for silicon in germanium and calculated as 0.85 and 0.95 for the Ge 77.5Si22.5 and Ge 52.4Si47.6 alloys respectively.
22(2015); http://dx.doi.org/10.1116/11.20150202View Description Hide Description
α-Fe2O3 matrices were deposited on Fluorine-doped Tin Oxide (FTO) substrates by Plasma Enhanced-Chemical Vapor Deposition (PE-CVD) from Fe(hfa)2TMEDA (hfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedionate; TMEDA = N,N,N′,N′-tetramethylethylenediamine). The obtained nanosystems were subsequently functionalized by platinum nanoparticles (NPs) via Radio Frequency (RF)-sputtering, exposing samples either to a pre- or post-sputtering thermal treatment at 650 °C for one hour in air. Interestingly, Pt oxidation state in the final composite systems strongly depended on the adopted processing conditions. In this work, a detailed X-ray Photoelectron Spectroscopy (XPS) analysis was carried out in order to investigate the material chemical composition, with particular regard to the relative Pt(0)/Pt(II)/Pt(IV) content. The obtained results evidenced that, when annealing is performed prior to sputtering, only PtO and PtO2 are revealed in the final Pt/α-Fe2O3 nanocomposite. In a different way, annealing after sputtering results in the co-presence of Pt(0), Pt(II) and Pt(IV) species, the former arising from the thermal decomposition of PtO2 to metallic platinum.