Polymethylmethacrylate (PMMA) is a positive tone photoresist, which undergoes chain scission under extreme ultraviolet exposure and is often used as a model photoresist for mechanistic studies due to its simplicity. Nano projectile secondary ion mass spectrometry (NP-SIMS) can be used to gain chemical information about the surface composition of a sample. NP-SIMS involves the bombardment of the sample surface with primary ions and the collection of the ejected secondary ions. The primary ions, Au4004+, are separated in time and space, and this enables the analysis of the secondary ions from each individual impact. Thin films (≈25 nm thick) of spin-cast PMMA of different molecular weights (35, 200, 495, and 950 kDa) on the silicon substrate were investigated regarding postincident fragmentation patterns. Three circular areas of 125 μm diameter were analyzed, and a total of 1–1.5 × 106 spectra were taken for each sample.
The optical functions of crystalline paratellurite (alpha-TeO2) and amorphous TeO2 were determined using several optical techniques: (1) standard spectroscopic two-modulator generalized ellipsometry (2-MGE) of paratellurite (200-850 nm, 6.2-1.46 eV), (2) near-normal-incidence two-modulator generalized ellipsometry microscopy (2-MGEM) of paratellurite (577 nm, 2.15 eV), (3) Mueller matrix transmission of paratellurite (320-798 nm, 3.87-1.55 eV), and (4) polarized transmission of paratellurite (323.6-334.3 nm, 3.83-3.71 eV). The 2-MGE measurements yielded highly accurate values of the dielectric functions and error estimates from 1.46 to 6.2 eV for both paratellurite and amorphous TeO2, whereas the polarization-dependent transmission yielded more accurate values of the absorption coefficient below the band edge of paratellurite. The 2-MGEM measured the diattenuation of paratellurite, which is related to the birefringence. Mueller matrix transmission measurements of paratellurite of a (001) cut crystal as a function of angle of incidence were used to determine both the birefringence and the rotary power as a function of photon energy.
Monochromatic Al Kα (1486.6 eV) and monochromatic Cr Kα (5414.8 eV) radiation sources were used to acquire x-ray photoelectron spectroscopy (XPS) and hard x-ray photoelectron spectroscopy (HAXPES) data on bulk semimetallic HgTe. The reported spectra include survey scans, high-resolution core-level spectra of Hg and Te, and x-ray-excited Auger transitions. These data provide reference binding and kinetic energy values and are intended to support future XPS and HAXPES studies of HgTe and related materials.
Polymer coatings with tailored properties have enabled advances and innovations in industry, biomedicine, sensorics, and consumer goods. The optimization of the functionality and the development of new applications require the comprehensive characterization of the material properties. Along with other methods, time-of-flight secondary ion mass spectrometry is applied for this purpose. Here, we provide reference spectra for Teflon (TM) AF 1601, a soluble, amorphous fluoropolymer with applications in innovative fields such as opto-electronics, microfluidics, and sensorics. Spectra were measured with positive and negative polarity using a 30 kV Bi-3(++) primary ion beam.
Trimethylsilyl-functionalization via N-(trimethylsilyl)dimethylamine (TMSDMA) vapor exposure is used by the semiconductor industry to selectively passivate SiO2 surfaces during area selective deposition. Although the effectiveness of this molecule at inhibiting deposition has been studied, there have been very few published journal articles that include XPS analysis of this passivated SiO2 surface. In addition, none of these studies provide high-resolution deconvolution of the XPS peaks associated with the adsorbed siloxyl groups. To help rectify this, XPS was used to analyze coupons cleaved from a TMSDMA-treated, 5 nm plasma-oxidized SiO2/Si(100) wafer. High-resolution, angle-resolved XPS spectra of the Si 2p, C 1s, and O 1s core regions were collected at an emission angle of 80 degrees with respect to the surface normal. Initial attempts to analyze the functionalized surface revealed that the molecular films degrade rapidly during analysis. In order to mitigate degradation of the organic monolayer, single-scan measurement sets (Si 2p, C 1s, and then O 1s) were performed on 78 separate analysis spots, which limits the x-ray exposure time of the functional groups at each measurement spot to 3 min. The spectra were then averaged to produce the high-resolution narrow-energy core spectra of the Si 2p, C 1s, and O 1s regions. This analysis technique, in conjunction with the high surface sensitivity of the angle-resolved XPS measurements at an emission angle of 80 degrees, has made it possible to identify the O-Si(CH3)(3) and Si-CH3 chemical shifts within the Si 2p and C 1s regions, respectively.
This paper presents the characteristics and operating modes of the PHI VersaProbe family of scanning x-ray photoelectron spectroscopy (XPS) microprobe instruments in detail to support accurate referencing in scientific publications and to provide readers with instrumental context often missing in research articles. The PHI VersaProbe is a commercial laboratory-based, multitechnique XPS system designed for spatially resolved surface analysis of a wide range of materials under ultrahigh vacuum conditions. An overview of the instrument's architecture, component geometries, and tables of key geometry as well as operator-selected parameters are provided. The paper details hardware and software configurations across multiple instrument generations and various data acquisition modes. Raw data from PHI VersaProbe instruments, collected from sputter-cleaned silver and polyethylene terephthalate samples, are included in the Surface Science Spectra submission. Figures throughout the paper compare performance characteristics across multiple instrument generations-PHI VersaProbe 4, PHI VersaProbe III, PHI VersaProbe II, and PHI VersaProbe I-that highlight how analyst-controlled variables such as analyzer pass energy influence analyzer energy resolution. Information that needs to be reported on experiments performed using the PHI VersaProbe is also discussed.
Diamond is a wide bandgap material with outstanding structural and electronic properties, making it a promising candidate for applications in radiation detection, energy conversion, and electrochemistry. Among its characteristics, the electronic behavior of the surface plays a pivotal role. Hydrogen termination can enable efficient electron emission, whereas the incorporation of nitrogen during chemical vapor deposition (CVD) growth modifies the defect structure and electrical conductivity. Such effects are particularly relevant for electrochemical processes, where emitted electrons can become solvated in aqueous environments, acting as powerful reducing agents. In this study, we investigate CVD nanocrystalline diamond films deposited on polycrystalline diamond plates, focusing on the influence of nitrogen incorporation and post-growth hydrogen plasma treatment on their properties. Through x-ray photoelectron spectroscopy (XPS) analysis, we assess material quality and chemical states of the various C, O, and N moieties present in the target samples. Our findings may provide new insights into how surface chemistry and defect engineering control the functional response of diamond in technologically relevant environments.
Nickel hydroxide is a key material for batteries, supercapacitors, and electrocatalysis. In this study, hard x-ray photoelectron spectroscopy (HAXPES) using 5951 eV photons was employed to probe deep-core levels of commercial Ni(OH)(2) powder with enhanced bulk sensitivity. The Ni 2p and Ni 2s HAXPES spectra are presented, showing characteristic multiplet and satellite features in the Ni 2p region and a significant chemical shift of the Ni 2s peak relative to reported values for metallic Ni.
Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is increasingly applied in life sciences to analyze composition and structure of extracellular matrices (ECMs). The fragmentation of the ECM components during the analysis results in a large number of individual signals in the mass spectra. Due to the chemical similarity of the biomolecular building blocks, identical fragments from different molecules can contribute to the same signal. Reliable reference spectra and multivariate methods are required in order to decipher the information hidden in ToF-SIMS spectra of complex ECM samples. Here, we provide reference spectra for collagen I, an important structural protein found in the ECM of mammals, including humans. These spectra were measured with positive and negative polarity using a 30 kV Bi-3(++) primary ion beam.
A ( (-)201 )-oriented beta-Ga2O3 (beta-gallium oxide) single crystal wafer, 2 in. in diameter, was diced into 5 & times; 5 mm(2) specimens for surface chemical analysis using x-ray photoelectron spectroscopy (XPS). To ensure accurate surface characterization, both ex situ and in situ pretreatment methods were employed to effectively remove surface contaminants. XPS data collection included a comprehensive survey spectrum and high-resolution core-level scans of Ga 2p, Ga 3s, Ga 3p, Ga 3d, O 1s, and C 1s, along with valence band spectra and Ga LMM and O KLL x-ray induced Auger electron spectroscopy (XAES) transitions. The oxidation state identified in all gallium and oxygen photoelectron lines corresponds to Ga3+, indicating the presence of the beta-Ga2O3 phase. Additionally, organic oxides and hydrocarbons were detected after 300 degrees C UHV annealing, which indicates the presence of strongly bonded species and an elevated number of dangling bonds on the ( (-)201 ) surface. The Ga and O Auger features further corroborate the oxidation state assignments and offer additional insight into the surface chemical environment of the beta-Ga2O3 specimens.
A 2-in. beta-Ga2O3 (beta-gallium oxide) single-crystal wafer of (001) orientation was diced into 5 & times; 5 mm(2) specimens, and its surface was characterized via x-ray photoelectron spectroscopy (XPS). Both ex situ and in situ pretreatments were conducted prior to XPS to eliminate surface contamination. Comprehensive spectra were acquired, including a wide survey scan and high-resolution core-level scans of Ga 3d, Ga 3p, Ga 3s, Ga 2p, O 1s, and C 1s, along with the valence band spectra and Ga LMM and O KLL x-ray induced Auger electron spectroscopy (XAES) transitions. The oxidation state observed across all gallium and oxygen core levels corresponds to Ga & sup3;(+), which, when combined with the quantitative analysis results, supports the presence of a stoichiometric beta-Ga2O3 phase. Carbon contamination was found to be negligible, indicating a clean surface with minimal adventitious carbon. The presence and spectral features of the Ga and O Auger lines further substantiate the oxidation state assignments and provide complementary insights into the surface chemical environment.
The surface chemistry of a (010)-oriented beta-Ga2O3 (beta-gallium oxide) single crystal was investigated using x-ray photoelectron spectroscopy (XPS). A 2 in. wafer was sectioned into 5 & times; 5 mm(2) specimens, and both ex situ and in situ surface cleaning procedures were incorporated to minimize contamination prior to analysis. XPS measurements included a wide energy survey and high-resolution scans of Ga 2p, Ga 3s, Ga 3p, Ga 3d, O 1s, and C 1s core levels, as well as the valence band region and Ga LMM and O KLL x-ray induced Auger electron spectroscopy (XAES) transitions. The spectra consistently revealed Ga3+ as the only oxidation state, in agreement with the expected chemical state for beta-Ga2O3. Additionally, the composition derived from the quantitative analysis indicates the existence of stoichiometric Ga2O3. Carbon was present only at trace levels, reflecting an effectively cleaned surface. The Auger transitions of Ga and O provided complementary confirmation of oxidation states and contributed to a more comprehensive understanding of the surface electronic structure.
Manganese iron oxide (MnFe2O4), an environmentally friendly material, has been the subject of numerous studies for a broad range of technological end-uses. In the present work, we focus on an x-ray photoelectron spectroscopy investigation of a representative MnFe2O4 specimen grown by chemical vapor deposition on fluorine-doped tin oxide. The material was fabricated starting from homologous beta-diketonate diamine Mn(II) and Fe(II) molecular precursors in an O-2 + H2O atmosphere, followed by ex situ annealing in an inert atmosphere. Beside the survey scan, we present and discuss high-resolution C 1s, O 1s, Mn 2p, Mn 3s, and Fe 2p spectra, recorded using a monochromated Al K-alpha x-ray source. Our findings provide valuable comparative data for researchers working on the preparation and characterization of manganese ferrite-containing systems for a wide range of applications.
Electronic states of bulk lithium were measured by hard x-ray photoelectron spectroscopy and XPS. The samples were measured using Cr K-alpha and Al K-alpha excitation sources at 5414.8 and 1486.6 eV, respectively, including survey, Li 1s, O 1s, and F 1s spectra were obtained.
Platinum silicide has garnered increased attention due to its potential applications as a superconductor within silicon technology. In this work, we characterize a superconducting PtSi film using x-ray photoelectron spectroscopy with an Al Kα excitation source. Survey spectra, Pt 5s, Pt 4f, Pt 4d, Pt 4p, Pt 4s, Si 2p, Si 2s, O 1s core levels, and the valence band spectrum were measured. This collection of high-quality core level spectra of a superconducting PtSi film provide reference data for this material, which often has a minimal native silicon oxide layer and overlapping Si and Pt core level peaks.
Plutonium metal oxidizes by forming an oxide layer on the surface. This oxide layer consists on Pu2O3 and PuO2. Photoelectron spectroscopy allows us to evaluate the growth kinetics of both oxides. A metal surface of a PuGa1 at. %, free of contamination, was prepared and oxidized by O-2 exposures at ambient temperature. The Pu 4f core level exhibits clearly the progress of the formation of the different oxidation states as a function of exposure time.
The characteristics and operation modes of the IONTOF Qtac high resolution low energy ion scattering spectrometer are described in sufficient detail that they can be referenced by authors using such instruments and provide readers with a level of instrumental detail often lacking in research papers. The Qtac analyzer is a commercial version of a double toroidal analyzer optimized for collection of low energy ion scattering data. Included is an instrument overview with a description of components and geometries, a table of relevant parameters, and some example data that relate to instrument performance.
There is a problem of sample composition change under the influence of ion beam. Therefore, in this article, we aim to not only supplement or refine the data (for statistical purposes) but also to provide the positions of the peaks formed by the compounds. This will contribute to a better understanding of the impact of ion beam on sample composition and aid in further analysis and interpretation of the results.
The ternary III-V semiconductor GaInP is a leading candidate material for the fabrication of ultra-bright red mu LED (microlight emitting diodes) structures for application in high-resolution display technologies. When the pixel pitch is reduced to below 10 mu m, increased nonradiative sidewall recombination in the active region of LEDs adversely affects the device's optical performance. The cause of this effect is a result of impurities in the lattice arising during the manufacture process. Correlating an understanding of the surface chemistry following the etch processes used to fabricate the mesa structured mu LED arrays with the optical performance is essential to develop fabrication approaches to maximize the internal quantum efficiency of the fabricated quantum well structures. In this study, high intensity hard x-ray photoelectron spectroscopy measurements, acquired at a photon beam energy of 6 keV, have been used to acquire reference spectra of the chemical composition of epitaxially grown planar lattice matched Ga0.51In0.49P on a GaAs up to a sampling depth of approximately 20-30 nm into the bulk region of the sample. Using the National Institute of Standards and Technology Spectroscopy Soft and Tender II beamline at the National Synchrotron Light Source, Brookhaven National Laboratory, a survey scan of the sample along with high-resolution scans of key core levels In 3d, Ga 2p, Ga 3d/In 4d, P 1s, P 2p, and contaminant O 1s were obtained to provide baseline photoemission data on chemical composition.
Perfluorosulfonic acids (PFSAs) are chemical compounds of the formula CnF(2n + 1)SO3H. PFSAs with six or more perfluorinated carbon atoms are referred to as long chain. These chemical compounds belong to the family of per- and polyfluoroalkyl substances, also known as so-called forever chemicals. Reference spectra in both polarities are presented of the potassium salts of one long-chain perfluorosulfonic acid, namely, perfluorooctanesulfonic acid with an eight-carbon fluorocarbon chain, and one short-chain perfluorosulfonic acid, namely, perfluorobutanesulfonic acid with a four-carbon fluorocarbon chain.
