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Delayed atomic layer deposition (ALD) of ZnO, i.e., area selective (AS)-ALD, was successfully achieved on silicon wafers (SiSiO2) terminated with tris(dimethylamino)methylsilane (TDMAMS). This resist molecule was deposited in a home-built, near-atmospheric pressure, flow-through, gas-phase reactor. TDMAMS had previously been shown to react with SiSiO2 in a single cycle/reaction and to drastically reduce the number of silanols that remain at the surface. ZnO was deposited in a commercial ALD system using dimethylzinc (DMZ) as the zinc precursor and H2O as the coreactant. Deposition of TDMAMS was confirmed by spectroscopic ellipsometry (SE), X-ray photoelectron spectroscopy (XPS), and wetting. ALD of ZnO, including its selectivity on TDMAMS-terminated SiSiO2 (SiSiO2TDMAMS), was confirmed by in situ multi-wavelength ellipsometry, ex situ SE, XPS, and/or high-sensitivity/low-energy ion scattering (HS-LEIS). The thermal stability of the TDMAMS resist layer, which is an important parameter for AS-ALD, was investigated by heating SiSiO2TDMAMS in air and nitrogen at 330 °C. ALD of ZnO takes place more readily on SiSiO2TDMAMS heated in the air than in N2, suggesting greater damage to the surface heated in the air. To better understand the in situ ALD of ZnO on SiSiO2TDMAMS and modified (thermally stressed) forms of it, the ellipsometry results were plotted as the normalized growth per cycle. Even one short pulse of TDMAMS effectively passivates SiSiO2. TDMAMS can be a useful, small-molecule inhibitor of ALD of ZnO on SiSiO2 surfaces.

Delayed atomic layer deposition (ALD) of ZnO, i.e., area selective (AS)-ALD, was successfully achieved on silicon wafers (Si/SiO2) terminated with tris(dimethylamino)methylsilane (TDMAMS). This resist molecule was deposited in a home-built, near atmospheric pressure, flow-through , gas-phase reactor. TDMAMS has been shown to react with Si/SiO2 in a single cycle/reaction and to drastically reduce the number of silanols that remain at the surface. ZnO was deposited in a commercial ALD system using dimethylzinc (DMZ) as the zinc precursor and H2O as the coreactant. Deposition of TDMAMS was confirmed by spectroscopic ellipsometry (SE), X-ray photoelectron spectroscopy (XPS), and wetting. ALD of ZnO, including its selectivity on TDMAMS – terminated Si/SiO2 (Si/SiO2/TDMAMS), was confirmed by in situ ellipsometry, ex situ SE, XPS, and/or high sensitivity – low energy ion scattering (HS-LEIS). The thermal stability of the TDMAMS resist layer, which is an important parameter for AS-ALD, was investigated by heating Si/SiO2/TDMAMS in air and nitrogen at 330 ºC. ALD of ZnO takes place more readily on Si/SiO2/TDMAMS heated in the air than in N2, suggesting greater damage to the surface heated in the air. To better understand the in situ ALD of ZnO, the data were also plotted as the normalized growth per cycle and to show the selectivity. Even one, short pulse of TDMAMS effectively passivates Si/SiO2. TDMAMS can be an effective small molecule inhibitor of ALD of ZnO on Si/SiO2 surfaces.

International audience; The existence of asymmetry in X-ray photoelectron spectroscopy (XPS) photoemission lines is widely accepted, but line shapes designed to accommodate asymmetry are generally lacking in theoretical justification. In this work, we present a new line shape for describing asymmetry in XPS signals that is based on two facts. First, the most widely known line shape for fitting asymmetric XPS signals that has a theoretical basis, referred to as the Doniach-Sunjic (DS) line shape, suffers from a mathematical inconvenience, which is that for asymmetric shapes the area beneath the curve (above the x-axis) is infinite. Second, it is common practice in XPS to remove the inelastically scattered background response of a peak in question with the Shirley algorithm. The new line shape described herein attempts to retain the theoretical virtues of the DS line shape, while allowing the use of a Shirley background, with the consequence that the resulting line shape has a finite area. To illustrate the use of this Doniach-Sunjic-Shirley (DSS) line shape, a set of spectra obtained from varying amounts of graphene oxide (GO) and reduced GO on a patterned, heterogeneous surface are fit and discussed.

International audience; While peak fitting of spectra/data is frequently performed in science, recent reports suggest that the quality of peak fitting in the scientific literature is often inadequate. Here, we describe a new statistical tool for determining the quality of fitting protocols, illustrating this capability with X-ray photoelectron spectroscopy (XPS) data. This tool, box plots of random starting conditions and their results, helps identify local minima in the multidimensional fit space of the fit parameters. Ideally, there should be a single global minimum for a fitting protocol such that different, reasonable starting conditions lead to the same result. To determine whether a fit space contains multiple local minima, a series of reasonable starting conditions is randomly chosen for the fit. If the boxes in the box plot of the peak areas of these multiple fits are narrow, the different possibilities converge to a single global minimum. Conversely, if the boxes are wide, multiple local minima are present. This method is related to the mathematical concept of ‘disproof by contradiction’. Our approach is demonstrated with four- and ten-component fits to a moderately complex C 1s XPS narrow scan. The results from our analysis compare favorably to those of traditional Monte Carlo analyses and uniqueness plots, where box plots are also applied to the Monte Carlo results, and each of these statistical tools performs a different function/probes a fit space/protocol differently.

The glucose oxidation reaction (GOR) is strictly controlled by the surface structure of an electrode. Here, we report the effect of potentiostatic deposition (PSD), potentiocyclic deposition (PCD), and a combination of these two modes (PSD/PCD) for platinum deposition on a carbon-based substrate as an electrocatalyst for an alkaline GOR. An optimized electrode results in current density of 18 mA cm−2 at −0.3 V, open circuit potential of −0.85 V, exchange current density of 2.11 mA cm−2, charge transfer resistance of 89.01 Ω cm−2 and a low diffusive behavior toward GOR. The total Pt loadings for these electrodes are PCD > PSD > PSD/PCD, while the Pt quantity on top of the electrode surface is PSD/PCD > PCD > PSD. These results illustrate that applying PSD prior to PCD reduces Pt loading, helps the formation of Pt particles at the top surface, and thus leads to better electrocatalytic activity toward GOR.

This study was undertaken to understand the extent and nature of problems in x-ray photoelectron spectroscopy (XPS) data reported in the literature. It first presents an assessment of the XPS data in three high-quality journals over a six-month period. This analysis of 409 publications showing XPS spectra provides insight into how XPS is being used, identifies the common mistakes or errors in XPS analysis, and reveals which elements are most commonly analyzed. More than 65% of the 409 papers showed fitting of XP spectra. An ad hoc group (herein identified as "the committee") of experienced XPS analysts reviewed these spectra and found that peak fitting was a common source of significant errors. The papers were ranked based on the perceived seriousness of the errors, which ranged from minor to major. Major errors, which, in the opinion of the ad hoc committee, can render the interpretation of the data meaningless, occurred when fitting protocols ignored underlying physics and chemistry or contained major errors in the analysis. Consistent with other materials analysis data, ca. 30% of the XPS data or analysis was identified as having major errors. Out of the publications with fitted spectra, ca. 40% had major errors. The most common elements analyzed by XPS in the papers sampled and researched at an online database, include carbon, oxygen, nitrogen, sulfur, and titanium. A scrutiny of the papers showing carbon and oxygen XPS spectra revealed the classes of materials being studied and the extent of problems in these analyses. As might be expected, C 1s and O 1s analyses are most often performed on sp2-type materials and inorganic oxides, respectively. These findings have helped focus a series of XPS guides and tutorials that deal with common analysis issues. The extent of problematic data is larger than the authors had expected. Quantification of the problem, examination of some of the common problem areas, and the development of targeted guides and tutorials may provide both the motivation and resources that enable the community to improve the overall quality and reliability of XPS analysis reported in the literature Refereed/Peer-reviewed

There are several methods to prepare electro-catalysts for low temperature fuel cells. Platinum is used as a common electro-catalyst for this purpose. Electrodeposition method is applied for preparing platinum on modified carbon paper as electrode directly. Many parameters effect on performance of prepared electrodes. At this work, the effect of type of electrolyte in electrodeposition solution was investigated for making electro-catalyst that is be used as anode in Glucose Alkaline Air Fuel Cell (GAAFC). Cyclic voltammetry ((1.2-0.6) V vs. Ag/AgCl sat. KCl, 100 mV/S) is used as electrodeposition method. Number of CV cycles is varied 10 to 50. Electrodeposition was performed in two precursor solution (0.5 M) containing phosphate and sulfate anions. Platinum concentration in solution was 3 mM. The prepared electro-catalysts were studied for Glucose Oxidation Reaction (GOR) by CV analysis in 0.3 M glucose solution and 0.5 M KOH. Also, Electrochemical Impedance Spectroscopy (EIS) method was used. According our results, the type of anion in electrodeposition solution affects on properties of prepared platinum electro-catalyst for GOR. Optimized condition for number of CV cycles in phosphate and sulfate solutions is 10 and 40 respectively. Article DOI: https://dx.doi.org/10.20319/mijst.2016.s11.91102 This work is licensed under the Creative Commons Attribution-Non-commercial 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc/4.0/ or send a letter to Creative Commons, PO Box 1866, Mountain View, CA 94042, USA.