Ar+ sputtering

Figure 3 Depth profiles of F implanted into 2000 A Si on Si02 la) SALI profile with Ar sputtering and 248-nm photoionization and (b) positive SIMS profile with O2 sputtering. Analytical conditions SALI, SiF profile) 7-keV Ar, 248 nm SIMS, F profile) 7-keV02 ...

To explore the possibility of electronic Interaction between the reduced titanium oxide and Pt, 1 ML of Pt was deposited on both fully oxidized and partially reduced T102. The reduced sample was prepared by Ar" " sputtering of the TIO2 substrate prior to metal deposition. Introducing reduced Tl centers at the Pt-Tl Interface. 

Figure 5. Morphology and particle size distribution of an island silver thin film deposited on native oxide covered silicon (a) before ion bombardment and after (b) 0.5 keV Ar sputtering with 1.1 X 10, (c) 2.5 X 10, and (d) 3.9 x 10 ion/cm dose. Sputtering speed for silver was around 3-4ML/min. Total elapsed sputtering time is indicated on each size distribution graphs. (Reprinted from Ref [123], 2003, with permission from Springer.)...

We prepared thin film Pt alloy electrodes by Ar-sputtering Pt and the second metal targets simultaneously onto a disk substrate at room temperature (thickness approximately 200 nm). The resulting alloy composition was determined by gravimetry and X-ray fluorescent analysis (EDX). Grazing incidence (i7= 1°) X-ray diffraction patterns of these alloys indicated the formation of a solid solution with a face-centered cubic (fee) crystal stmeture. 

Fig. 8. Capacitance transient spectra recorded under the same conditions for Ar+ sputter etched n-type Ge. (a) substrate temperature 25°C during sputtering, (b) substrate temperature 100°C during sputtering and (c) after sputter etching and hydrogenation at 180 C for 20 min. (Pearton et al., 1983).

Figure 4. Elemental peak intensities versus duration of Ar+ sputtering in obsidian.

In addition, the sample prepared with BMI PF was submitted to Ar sputtering followed by further XPS analysis. After sputtering, the F Is signal was eliminated as well as the Ir—F component in the Ir 4f region (which displays mainly the Ir—Ir component), showing that only the external surface iridium atoms were bounded to F (Figure 15.6). These results indicated strongly that, besides the presence of an Ir—O layer, it was the effective interachon of the IL with the metal surface that may have been responsible for stabilization of the nanoparhcles. 

Figure 15.6 X-ray photoelectron spectroscopy of the Ir4f region for lr(0) nanoparticles prepared in BMI PFs before and after Ar sputtering. Ar sputtering eliminates the...

The vanadium-containing materials have been characterised further by XRD, TPR, laser Raman spectroscopy and XPS in combination with Ar -sputtering. The influence of various catalyst pretreatments on the catalytic performance has also been investigated. 

The results of XPS combined with Ar" -sputtering on a VlNb imp.-sample are shown in Figure 4. In this figure, sputtering profiles are shown for a fresh catalyst and for one which had been used for 300h at 510 °C (at this temperature 100% oxygen conversion was reached, no deactivation was observed). Since XRF showed that no vanadium was lost from the catalyst, it can be concluded that in the fresh catalyst, vanadium is present in a homogeneous layer which is at least 40-80 A thick. Upon use, sub-surface vanadium has diffused into the bulk of the catalyst, while the surface concentration of vanadium remains the same. The vanadium at the surface was found to be mostly V " in both the fresh and the used catalyst. Because of the low concentrations of vanadium at the surface and interference from the Ols peak, the presence of small amounts of reduced vanadium cannot be excluded. 

Figure 4 Ar -sputtering profiles as determined by XPS for a VlNb imp.-catalyst. Sputtering rate 1-2 A/min.

Recent UPS/XPS measurements have been performed in our laboratory on UO2.0 single crystals the surface of which had been prepared in different ways (Ar -sputtering in situ scraping). These results are shown in Fig. 22 and illustrate the 5f character of... 

XPS will aid in understanding specifically the surface of the black deposit covering pictographs in Little Lost River Cave in Idaho. This work will complement other bulk analyses carried out with pyrolysis-GC-MS and thermally assisted hydrolysis /methylation (THM)-GC-MS (75). The objectives of this project were to use XPS to qualitatively determine the surface elemental composition of the black residue semiquantitatively characterize the surface, for comparison with other surface-related materials and examine the relationship between the chemistry and depth by using Ar+ sputtering. This, then, will aid in validating the radiocarbon date obtained through plasma-chemical oxidation and accelerator mass spectrometry by Steelman et al. (5). 

Semi-quantitative results obtained from XPS analyses after Ar+ sputtering (4 kV, 100 iA) and using the Scofield sensitivity factors see J.H. Scofield. J. Electron. Spectros. Rel. Phenom., 8,129 (1976). Overestimated values C recontamination of the surface due to the use of separate sputtering and analysis chambers. 

UPS spectra of clean Ar+ sputtered and in Vacuo carbon-contaminated surfaces are shown in Figure 4. On the clean, sputtered surface a filled state due to Ti3+ lies 0.6 eV below the conduction band.(22) Carbon-induced filled states lie in a broad peak with considerable intensity between the valence band edge and the Ti + peak. Frank et al.lQ) reported evidence that a state lying about 1.2 eV above the valence band mediates electron transfer from Ti02 electrodes. Although these carbon states are as of now poorly defined and have not been directly implicated in any aqueous photochemistry, their nearly ubiquitous presence should be considered in discussions of charge transfer at real oxide surfaces. 

Figure 5. Details of oxygen Auger spectra of SrTiOs crystals (A) Ar -sputtered (B) illuminated in 7M O HtO (C) illuminated in 30% NaOH (D) illuminated in 10M NaClOy (E) illuminated in 1M HsSOt. Inflection point of main oxygen peak at 501 eV.

Figure 9. Auger spectra of (A) freshly Ar -sputtered surface (B) (A) exposed to room air 2 min (C) (A) exposed to 7M-n water for 1 min...

All XPS or ESCA measurements were performed using a Perkin Elmer 5300 ESCA spectrometer equipped with a dual anode (Mg, Al) X-ray source, differentially pumped Ar+ sputter gun, and the variable angle measurement set-up for angle-resolved photoelectron spectroscopic measurements. The data collection and treatment, e.g. smoothing, curve-fitting, intensity measurements, were accomplished by a Perkin Elmer 7500 dedicated computer system using PHI software package. 

Clean the rear side of the LAPS structure, with, e.g., an Ar-sputter process for 1 min. 

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