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Silver metal was analyzed by x-ray photoelectron spectroscopy using a Thermo Scientific K-Alpha instrument with an Al Kα x-ray source (1486.6 eV). The silver survey spectrum and high-resolution Ag 3d, Ag M4N45N45, Ag M5N45N45, Ag 3p, O 1s, C 1s, Ar 2p, Ag 4p, and Ag 4s narrow scans were obtained. The sample analyzed is the standard instrument calibration silver foil mounted inside the analysis chamber of the K-Alpha. Sputtering with monoatomic Ar+ was performed prior to analysis to remove surface contamination. Narrow and survey scans were collected at 50 and 200 eV pass energy, respectively. [ABSTRACT FROM AUTHOR]

This study considers how poor x-ray photoelectron spectroscopy (XPS) peak fitting in the scientific literature is both affected by previous precedent and affects future published work. It focuses on a highly cited paper (the "Subject" paper) from a respected journal that contains incorrect S 2p peak fits. This paper was studied in a genealogical fashion vis-à-vis the XPS peak fitting in its "child," "parent," "grandparent," and "great-grandparent" papers. Interestingly, precedents were not followed to a high degree between parent and child papers. However, in many cases, even when the authors of a study did not follow the incorrect precedent that they cited, they still incorrectly fit their data. Thus, not necessarily for good reasons, the effects of poor XPS peak fits on future generations of papers may be less than some experts had expected or feared. In many cases, older papers appear to contain better XPS peak fitting than newer ones. [ABSTRACT FROM AUTHOR]

In contrast to traditional X‐ray photoelectron spectroscopy (XPS), hard X‐ray photoelectron spectroscopy (HAXPES) can provide information from deeper within a sample while maintaining chemical resolution. However, working with higher energy X‐rays introduces a series of new or different issues ranging from energy calibration to factors associated with quantitative analysis. As part of the efforts to identify and increase community awareness about these issues, a workshop was held to review HAXPES metrology challenges with the perspective of converting it into a quantitative technique. A summary is hereby given of this workshop, which was entitled "What New Challenges Come with the Capabilities of HAXPES?" It was held in Portland, OR, USA, on November 7, 2023, and was primarily sponsored by the ASTM E42 Committee and the Applied Surface Science Division of the American Vacuum Society. This report contains summaries of the presentations and discussions at this workshop regarding the current open problems in HAXPES metrology. There were 20 participants at the workshop. [ABSTRACT FROM AUTHOR]

Immersion ellipsometry can break the well-known correlation between optical constants and thicknesses of ultrathin (<5–10 nm) films, allowing both to be determined. In immersion ellipsometry, ellipsometric data is acquired in air and liquid ambients, and the data sets are combined in the analysis. The contrast in index between the liquid and film adds information to the analysis that breaks the correlation between the film thickness and refractive index that exists for air-only measurements. We describe the theory and practice of immersion ellipsometry. We also discuss the use of multiwavelength immersion ellipsometry to measure the thicknesses and optical constants of two thin films: native oxide on silicon and an alkyl monolayer on that native oxide. The average thicknesses of the native oxide and chloro(dimethyl)octadecylsilane (CDMOS) monolayer were 1.526 ± 0.027 nm and 1.968 ± 0.057 nm, and their average indices of refraction at 633 nm were 1.519 ± 0.005 and 1.471 ± 0.004, respectively. The native oxide and CDMOS monolayer were also characterized with x-ray photoelectron spectroscopy (XPS) and contact angle goniometry. Both the XPS C 1 s peak and the water contact angle increased substantially after monolayer deposition. While immersion ellipsometry has been known for decades, its use has been limited, maybe due to a lack of awareness of the technique and/or the need to immerse the sample surface in a liquid that could be destructive if the sample is not compatible with the liquid. As ultrathin films become widely used in science technology, immersion ellipsometry should increase in importance. [ABSTRACT FROM AUTHOR]

Identification of similar and dissimilar spectra is an important part of analyzing X‐ray photoelectron spectroscopy (XPS) images. Cluster analysis (CA) is a commonly used exploratory data analysis (EDA) method that groups similar spectra in a data set. CA can be performed in either an agglomerative fashion, for example, using Ward's method, which involves successively linking together/clustering the most similar spectra in a data set, or in a divisive fashion, for example, using the K‐means approach, which involves partitioning all the data into a specified number of clusters. In this note, we show the application of CA to an XPS image dataset. The use of Ward's method identified two major clusters in the image, where one of the clusters appeared as two subclusters. The K‐means image based on two clusters agrees well with previous analyses of the same image. The average spectra corresponding to clusters helped confirm the assignments made by the CA algorithms, as did a multivariate curve resolution (MCR) analysis of the interior region identified in our cluster analysis. "Elbow" plots can help determine the number of clusters to keep in K‐means clustering. The combination of the agglomerative and divisive forms of CA, where the first informs the second, can be effective in revealing the structures of XPS image datasets. The Procrustean bed is a metaphor for overfitting and underfitting in EDA. [ABSTRACT FROM AUTHOR]

The plan view is used in crystallography and materials science to show the positions of atoms in crystal structures. However, it is not widely used in teaching general chemistry. In this contribution, we introduce the plan view, and show these views for the simple cubic, body-centered cubic, face-centered cubic, hexagonal close packed, CsCl, NaCl, diamond cubic, ZnS, and CaF[subscript 2] unit cells. A survey administered to college-level general chemistry students indicates that the plan view helps them to better understand crystal structures.

This Insight Note follows a series of three previous insight notes on X‐ray photoelectron spectroscopy image analysis that focused on the importance of analyzing the raw data, the use of summary statistics, and principal component analysis (PCA). The same X‐ray photoelectron spectroscopy image data set was analyzed in all three notes. We now show an analysis of this same data set using multivariate curve resolution (MCR). MCR is a widely used exploratory data analysis method. Because of MCR's nonnegativity constraints, it has the important advantage of producing factors that look like real spectra. That is, both its scores and loadings are positive, so its results are often more interpretable than those from PCA. The requirements for preprocessing data are also, in general, lower for MCR compared with PCA. To help determine the number of factors that best describe the data set, a series of MCR models with different numbers of factors was created. Based on the chemical reasonableness of its factors, a two‐factor model was selected. Scores plots/images show the regions of the image that correspond to these two factors. [ABSTRACT FROM AUTHOR]

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 had previously 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 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 Si\SiO2\TDMAMS in air and nitrogen at 330 °C. 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 on Si\SiO2\TDMAMS 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 Si\SiO2. TDMAMS can be a useful, small-molecule inhibitor of ALD of ZnO on Si\SiO2 surfaces. [ABSTRACT FROM AUTHOR]