X-ray Photoelectron Spectroscopy Features Research Articles

Chemical information from XPS: Theory and experiment for Ni(OH)2.

The features and the electronic character of the states for the Ni 2p x-ray photoelectron spectroscopy (XPS) of Ni(OH)2 were analyzed. This detailed analysis is based on abinitio molecular orbital wavefunctions for a cluster model of Ni(OH)2. The theory is validated by comparison with experiment. Then, advanced methods are used to explain and contrast the properties of different groups of ionic states. An important conclusion is that in most cases, the ionic states cannot be described with a single configuration or determinant. Despite this essential many-body character of the XPS, we demonstrate that it is possible to understand the origin of the main and satellite XPS features in terms of their orbital character.

A step toward correct interpretation of XPS results in metal oxides: A case study aided by first-principles method in ZnO.

Metal oxide semiconductors constitute a vast group of materials whose physical properties are greatly affected by native defects. For decades, x-ray photoelectron spectroscopy (XPS) has been widely used in defect analysis. However, correct interpretation of XPS results remains a difficult task. In this work, we present a detailed first-principles study on the core-level shift of the most stable and commonly cited crystal imperfections in ZnO, including O and -OH species at the surface with different coverages and bulk defects, including O interstitial (Oi), O vacancy in the +2 charge state (Vo2+), and the neutral vacancy (Vo0). The O1s core level spectrum is simulated and compared with experiments to understand the correlation between local atomic structures and features in the O1s spectrum. In particular, our results indicate that the widely adopted assignment in the defect analysis of ZnO, which links the defect peak in XPS to Vo, the most stable defect, is very likely a misinterpretation. Theoretical analysis indicates that there are no distinguishable XPS features arising from the Vo defect. Furthermore, we show that the commonly observed defect-related peak instead arises due to Oi or specific surface configurations. Given the importance of native defects in materials performance, misinterpretation of XPS results may lead to erroneous conclusions regarding materials properties. This work provides a first-principles basis for the analysis of oxide defects through XPS.

XPS determined mechanism of selenite (HSeO3−) sorption in absence/presence of sulfate (SO42−) on Mg-Al-CO3 Layered double hydroxides (LDHs): Solid phase speciation focus

Success in adsorptive removal depends on solid phase speciation, which predetermines the extraction mechanism. This work investigates the mechanism of selenite (HSeO3−) sorption on Mg-Al Layered double hydroxides (LDHs), prepared by the original alkoxide-free sol-gel method, which already demonstrated outstanding removal of aqueous selenium species. Using X-ray Photoelectron Spectroscopy (XPS) as most relevant technique allowed to reveal the phase speciation in solid state as a function of two variables, competing sulfate and pH (8.5; 7.0; 4.5), and to detect the phases responsible for selenite uptake. Despite the leading initializing role of Mg-containing phases, selenite ended up to be chemically bound to one aluminium-based phase. The involvement of the second sorption mechanism via anion exchange of the interlayer carbonate with aqueous selenite depended on absence/presence of competing sulfate and pH. Comparison with the analogues results on selenate (SeO42−) sorption on the same material (published) resulted in discovery of the differences in XPS feature changes upon either physisorption or chemisorption. This is the first report, which discloses that physisorption of aqueous anion to a particular solid phase shifts the respective envelopment binding energies, whist chemisorptive binding causes considerable alterations (decreases/shifts) of XPS features of the specific binding solid species, such as Al(OH)3, however, it preserves nearly the same XPS characteristics of the envelopment peaks. Based on these discoveries, here we suggest a methodological idea on using the results of XPS analysis for interpretation of molecular mechanism of ion sorption on inorganic ion exchangers and to reliably distinguish the chemisorption from physisorption.

Main and Satellite Features in the Ni 2p XPS of NiO.

The origin and assignment of the complex main and satellite X-ray photoelectron spectroscopy (XPS) features of the cations in ionic compounds have been the subject of extensive theoretical studies using different methods. There is agreement that within a molecular orbital model, one needs to take into account different types of configurations. Specifically, those where a core electron is removed, but no other configuration changes are made and those where in addition to ionization, there are also shake or charge-transfer changes to the ionic configuration. However, there are strong disagreements about the assignment of XPS features to these configurations. The present work is directed toward resolving the origin of main and satellite features for the Ni 2p XPS of NiO based on ab initio molecular orbital wave functions (WFs) for a cluster model of NiO. A major problem in earlier ab initio XPS studies of ionic compounds has been the use of a common set of orbitals that was not able to properly describe all the ionic configurations that contribute to the full XPS spectra. This is resolved in the present work by using orbitals that are optimized for averages of the occupations of the different configurations that contribute to the XPS. The approach of using state-averaged (SA) orbitals is validated through comparisons between different averages and through use of higher order excitations in the WFs for the ionic states. It represents a major extension of our earlier work on the main and satellite features of the Fe 2p XPS of Fe2O3 and proves the reliability and the generality of the assignments of the character and origin of the different features of the XPS obtained with orbitals optimized for SAs. These molecular orbital methods permit the characterization of the ionic states in terms of the importance of shake excitations and of the coupling of ionization of 2p1/2 and 2p3/2 spin-orbit split sub shells. The work lays the foundation for definitive assignments of the character of main and satellite XPS features and points to their origin in the electronic structure of the material.

A rapid classification method of tea products utilizing X-ray photoelectron spectroscopy: Relationship derived from correlation analysis, modeling, and quantum chemical calculation

The classification of tea products is nowadays mainly determined by sensory assessment and chemical analysis methods. These methods are subjective, time-consuming, and laborious. In this work, a rapid analytical method for tea classification was proposed on the basis of X-ray photoelectron spectroscopy (XPS) and quantum chemical calculation. A total of 56 kinds of tea products were studied. By utilizing the data fusion strategy, the correlation between XPS peak parameters and tea characteristics was established. The quantum chemical calculations of the core-level ionization potentials deepen the understanding of the XPS features. The binding energy of the main fitted peak for O 1s, BE1O1s, was found to have a good correlation with tea polyphenols contents, which can be used to classify tea products into six tea types (black, dark, green, oolong, white, and yellow tea) with an accuracy greater than 90 %. The results suggest that the proposed XPS method is suitable for the rapid discrimination of tea classification, which contributes to the efficient application of tea.

Extracting Chemical Information from XPS Spectra: A Perspective

Important mechanisms that lead to features, often complex, in X-ray photoelectron spectroscopy (XPS) spectra are defined and described. It is shown that there is much information in an XPS spectrum that can be obtained by examining these features rather than examining only the shifts of main peaks between different materials. These mechanisms are presented with a focus on describing the underlying chemical and physical phenomena responsible for features of the XPS and on showing how these XPS features can be related to the properties and electronic structure of the material studied. While it is necessary to consider certain quantum mechanical rules, the mathematical formalism is not discussed. However, a general awareness of multiplet splittings, which are a result of angular momentum coupling combined with ligand field and spin–orbit splittings, and of covalent mixings in the metal–ligand bond of oxides is essential to properly interpret the significance of XPS features. A conceptual framework of shake excitation from bonding to anti-bonding orbitals is introduced to provide an understanding of the significance of XPS satellites. While the coupling of theory and measurement is required to extract quantitative information from XPS, it may be possible to obtain useful qualitative information directly from features of the XPS spectra provided that one takes into account more than only shifts of the XPS binding energies. A correct analysis of XPS features may require a careful treatment of many-body effects that distribute intensity over many individual, unresolved final states.

Thiol Adsorption on and Reduction of Copper Oxide Particles and Surfaces.

The adsorption of 1-dodecanethiol at room temperature and at 75 °C on submicron cuprous and cupric oxide particles suspended in ethanol has been investigated by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and transmission electron microscopy. Thiol adsorption occurs in all cases via Cu-S bond formation, with partial dissolution of CuO at 75 °C and formation of a copper-thiolate complex replacement layer. Regardless of temperature, the surface of the CuO particles is essentially completely reduced to either Cu2O or metallic copper, as evidenced by loss of the characteristic Cu(2+) XPS features of dried powder samples. Companion ultrahigh-vacuum studies have been performed by dosing clean, oxygen-dosed, and ozone-treated single crystal Cu(111) with methanethiol (MT) gas at room temperature. In the latter case, the surface corresponds to CuO/Cu(111). XPS confirms MT adsorption in all cases, with an S 2p peak binding energy of 162.9 ± 0.1 eV, consistent with methanethiolate adsorption. Heating of MT-covered Cu(111) and oxygen-dosed Cu(111) leads to decomposition/desorption of the MT by 100 °C and formation of copper sulfide with an S 2p binding energy of 161.8 eV. Dosing CuO/Cu(111) with 50-200 L of MT leads to only partial reduction/removal of the CuO surface layers prior to methanethiolate adsorption. This is confirmed by ultraviolet photoelectron spectroscopy (UPS), which measures the occupied states near the Fermi level. For both the colloidal CuO and single crystal CuO/Cu(111) studies, the reduction of the Cu(2+) surface is believed to occur by formation and desorption of the corresponding dithiol prior to thiolate adsorption.

Graphene as Electrophile: Reactions of Graphene Fluoride

Fluorinated graphene obtained by exposing single-layer CVD-grown graphene to xenon difluoride was reacted with a series of amine-, alcohol-, and sulfur-bearing nucleophiles, and the progress and nature of the reactions were monitored using X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and conductivity measurements. The results of these experiments indicate that amine and alcohol nucleophiles can displace the fluorine groups to form covalent bonds to the graphene. For nucleophiles with more than one possible reactive site, close examination of XPS features reveals the orientation of these groups on the graphene. Sulfur nucleophiles act preferentially as reducing agents, removing fluorine rather than replacing it. Finally, a proof-of-principle nucleophilic substitution is performed on bulk graphite fluoride, showing that the chemical functionality of graphite can be extended through nucleophilic substitution in an analogous manner to that of single-layer graphene.

Effect of Using Ethanol as the Oxygen Source on the Growth and Dielectric Behavior of Atomic Layer Deposited Hafnium Oxide

Use of common atomic layer deposition (ALD) oxygen sources such as oxygen, ozone or water often causes uncontrolled oxidation of the silicon surface by diffusion through the growing HfO2 film during the ALD process. This results in thick interfacial layer (IL) that is detrimental to future transistor scaling if further thinning of the IL is desired. In order to minimize the uncontrolled oxidation at the interface, we explored the use of ethanol as the ALD oxygen source in the ALD HfO2 process. The effect of using ethanol on the growth, composition and electrical behavior of ALD HfO2 films was studied and compared against films prepared using water based ALD process. Ethanol showed good reactivity with the hafnium precursor tetrakis(diethylamino)hafnium and displayed typical ALD growth behavior of linear film growth within a wide ALD process temperature window (200-280 °C). The ethanol based ALD process exhibited HfO2 growth rate of 0.05 nm/cycle which was less than 0.15 nm/cycle obtained when water was used as the ALD oxygen source. X-ray photoelectron spectroscopy (XPS) showed the deposition of stoichiometric HfO2 with trace amount of carbon in the film. SiO2 interfacial layer was not observed in as-deposited samples, whereas annealed samples showed SiO2 XPS features. Films prepared using the ethanol based ALD process showed comparable dielectric performance to that of water based ALD process films and displayed well behaved C-V and I-V curves with as-deposited (ethanol) HfO2 samples showing the lowest leakage current density of 5 x 10-8 A/cm2 at 1 V gate bias.

X-ray photoelectron spectroscopy of oxygen-containing layers formed by a linear potential scan on stepped gold (111) films in aqueous 1 M sulphuric acid

X-ray photoelectron spectroscopy (XPS) data of oxygen-containing layers (O-layers) made on stepped gold (111) film electrodes from aqueous 1 M sulphuric acid by single linear potential scans at 0.10 V s − 1 and 298 K are reported. The potential scan covered from the open circuit potential to anodic switching potential E as = 2.50 V versus normal hydrogen electrode (NHE) and holding times at E as in the range 30–300 s. The anodic charge density q a determined from the oxidation and reduction voltammetric scan is in the range 0.20 ≤ q a ≤ 2.5 mC cm − 2 . For the potential E = 0.5 V, in the absence of O-layers, the S 2p core level spectrum indicates the presence of sulphate/bisulphate adsorbates. For E as > 1.3 V, the O 1s core level spectrum involves the contribution from water, OH- and O-species. These spectra are deconvoluted utilising either three or four Gaussian contributions with values of peaked binding energy and full width at half-maximum height (FWMH) in good agreement with expectations. The envelope of these XPS O 1s signals after correction for the contribution of sulphate/bisulphate adsorbates and adventitious carbon approaches the XPS signal that has been reported for the core level spectrum in the O 1s region of oxidised gold surfaces produced by laser pulses at different molecular oxygen pressures. The O/OH concentration ratio in the O-layer increases with E as ageing time t ag and cathodic charge density q c. The hydrous nature of the O-layer, evaluated through the analysis of the core level spectra in the O 1s region, decreases as E as and t ag are increased. Results are interesting to unravel the composition and structure of electrochemically grown O-layers at the surface of the gold substrate, and the influence of the history of these O-layers on the respective XPS features.

Core-level electronic structure of solid-phase glycine, glycyl-glycine, diglycyl-glycine, and polyglycine: X-ray photoemission analysis and Hartree–Fock calculations of their zwitterions

X-ray photoelectron spectroscopy (XPS) has been used to investigate the core-level electronic structures of glycine (G) and its peptides, including glycyl-glycine (GG), diglycyl-glycine (GGG), and polyglycine (poly-G), in their powder forms. Increasing the number of G units in the peptides does not change the locations of the respective C 1s, N 1s, and O 1s features corresponding to different functional groups: -COO(-), -NH(3)(+), >CH(2), and -CONH-. The electronic structures of the zwitterions of these molecules have been calculated as isolated molecules and as molecules in an aqueous environment under the periodic boundary conditions by quantum-mechanical and molecular mechanics methods. In the case of glycine zwitterion, the binding energies of the C 1s, N 1s, and O 1s XPS features are found to be in reasonable accord with the respective orbital energies obtained by Hartree-Fock self-consistent-field calculations, within the context of Koopmans' approximation. However, considerably worse agreement in the binding energies is found for the larger zwitterions (with the specific conformations considered in this work), indicating the need for higher-level calculations. The present work shows that optimizing the zwitterion in an aqueous environment under the periodic boundary conditions by molecular mechanics could be a very cost-effective approach for calculating the electronic structures of large, complex biomolecular systems.

First‐principles characterization of amorphous carbon nitride systems: structural and electronic properties

AbstractA series of carbon nitride structures have been generated, by using a classical potential in a Metropolis Monte Carlo liquid quench procedure. The resulting structures are relaxed further using the density functional theory approach. Structures are generated for various mass densities and varying N/C ratio so that all possible C–N bonding configurations are produced. Structural analysis of the equilibrated structures are performed and the effect of nitrogen inclusion on the formation of curved carbon systems is evidenced. Density of states and energy‐loss near‐edge structure calculations show that nitrogen incorporation modifies the valence and conduction bands of amorphous carbon (a‐C). X‐ray photoelectron spectroscopy (XPS) calculations within the first‐principles methodology are also performed on the generated a‐C nitride systems. Depending on the carbon bonding configuration, the carbon 1s energies are found to vary from 283 eV to 288 eV while those of nitrogen are found to range from 397 eV to 402 eV. The experimentally observed N 1s XPS features of a‐C nitride systems are correlated with the nitrogen bonding state with carbon, the degree of delocalization of the nitrogen lone pair and the C–N bond length. In particular, our calculations support the interpretation of the N 1s feature at an energy of about 398.4 eV to two‐coordinated N atoms whose immediate neighbors enhance a delocalization of the N lone pair of electrons. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Spectroscopic Characterization of the Uranium Carbonate Andersonite Na2Ca[UO2(CO3)3]·6H2O

The uranium carbonate andersonite Na2Ca[UO2(CO3)3] x 6H2O was synthesized and identified with classical analytical and spectroscopic methods. The classical methods applied were powder X-ray diffraction (XRD), nitric acid digestion, and scanning electron microcopy combined with energy-dispersive spectroscopy (SEM/EDS). To characterize andersonite spectroscopically, time-resolved laser-induced fluorescence spectroscopy (TRLFS), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR) were used. Natural and synthetic andersonite samples were characterized with the nondestructive TRLFS by six fluorescence emission bands at 470.6, 486.1, 505.4, 526.7, 549.6, and 573.9 nm. In addition, andersonite was characterized by FT-IR measurements by the appearance of the asymmetric stretching vibration of the uranyl cation [v3(UO2(2+))] at 902 cm(-1) with a shoulder at 913 cm(-1). XPS measurements verified the composition of the synthetic andersonite sample. The measured intensity ratios of the XPS lines agree with the stoichiometry of Na2Ca[UO2(CO3)3] x 6H2O. The XPS features of the inner valence molecular orbitals are characteristic of the [UO2(CO3)3]4- structural moiety. These spectroscopic methods can be used to identify in a fingerprinting procedure secondary U(VI) phases in mixtures with other phases or as thin coatings on mineral and rock surfaces.

Electronic structures of ultra-thin silicon carbides deposited on graphite

Electronic structures of ultra-thin silicon carbide films have been investigated by X-ray photoelectron spectroscopy (XPS) and Si K-edge X-ray absorption near edge structure (XANES) using linearly polarized synchrotron soft X-rays. Silicon carbide films were deposited on the surface of highly oriented pyrolytic graphite (HOPG) by ion beam deposition method. Tetramethylsilane (Si(CH 3) 4) was used as a discharge gas. The XPS and XANES features for the thick layers were similar to those for the bulk SiC. For sub-monolayered films, the Si 1s binding energy in XPS was higher by 2.5 eV than that for bulk SiC. This suggests the existence of low-dimensional SiC x where the silicon atoms are more positively charged than those in bulk SiC. After annealing the sub-monolayered film at 850 °C, a new peak appeared around 1840 eV in the XANES spectrum. The energy of this new peak was lower than those for any other silicon compounds. The low-energy feature of the XANES peak suggests the existence of π *-like orbitals around the silicon atom. On the basis of the polarization dependencies of the XANES spectra, it was revealed that the direction of the π *-like orbitals are nearly perpendicular to the surface. We conclude that sub-monolayered SiC x film exhibits flat-lying structure of which configuration is similar to a single sheet of graphite.

The Reactivity of Linear Alkyl Carbonates toward Metallic Lithium : X-Ray Photoelectron Spectroscopy Studies in Ultrahigh Vacuum

X-ray photoelectron spectroscopy (XPS) was used to examine the reactivity of metallic Li toward gas-phase symmetric and asymmetric alkyl linear carbonates of the form (R and at room temperature in ultrahigh vacuum (UHV). Comparison of the C (1s) and O (1s) XPS features obtained in virtually identical experiments involving methanol and ethanol allowed and to be clearly identified as the major products of the reaction between Li and dimethyl (DMC) and diethyl (DEC) carbonates, respectively, and a mixture of the two alkoxides for ethylmethyl (EMC) carbonate. These findings are in agreement with UHV Fourier transform infrared studies of the same systems reported earlier in our laboratory. Also found in the XPS spectra for interfaces was an O (1s) peak at 529.6 eV attributed to Li oxide. In the case of DEC and EMC, evidence was obtained for the presence of an additional O (1s) feature at 534.76 eV attributed to Li ethyl carbonate. This behavior was unlike that found for DMC for which no signals due to Li methyl carbonate could be discerned. The conclusions emerging from this study further support the general mechanism for Li reactivity toward suggested by Aurbach and co-workers. © 2002 The Electrochemical Society. All rights reserved.

Nonlinear composition dependence of x-ray photoelectron spectroscopy and Auger electron spectroscopy features in plasma-deposited zirconium silicate alloy thin films

The local bonding of Zr, Si, and O atoms in plasma-deposited, and post-deposition annealed Zr silicate pseudobinary alloys [(ZrO2)x(SiO2)1−x] was studied by x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Systematic decreases in XPS binding energies, and increases in AES kinetic energies with alloy composition x are consistent with an empirical chemical bonding model based on electronegativity equalization; however, there are significant departures from the predicted linear composition dependencies of that model. Deviations from linearity in the XPS compositional dependencies are correlated with dipolar network atom fields as determined from ab initio calculations. The nonlinearities in the x dependence of ZrMVV and OKVV AES spectral features are determined primarily by oxygen–atom coordination dependent shifts in valence band offset energies. The energy spread in the compositional dependence of binding energies (∼1.85 eV) for the XPS Zr 3d5/2 and Si 2p features combined with x-ray absorption spectroscopy data indicates that the conduction band offset energies between the Si substrate and Zr silicate dielectrics are alloy composition independent. Changes in O 1s XPS features in alloys with x∼0.3 to 0.6 as function of annealing temperature are consistent with a previously identified chemical phase separation that occurs after 60 s anneals at 900 °C in a nonoxidizing ambient, Ar.

Adsorption Characteristics of Anthraquinone-2-carboxylic Acid on Gold

The adsorption of anthraquinone-2-carboxylic acid (AQ-2-COOH) on a gold surface has been investigated by reflection−absorption infrared (RAIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), surface-enhanced Raman scattering (SERS), quartz crystal microbalance (QCM), and ab initio quantum mechanical calculation. The RAIR spectral data clearly showed that the molecule was chemisorbed on gold as carboxylate, after deprotonation, with its two oxygen atoms bound symmetrically to the gold substrate; the molecular plane was determined to be tilted by 30° from the surface normal. The XPS and SERS spectral features were also consonant with the RAIR data. On the other hand, in CV, symmetrical redox peaks arising from a surface-confined species were reversibly identified at −647.5 mV, and the surface coverage determined from CV, that is, 1.8 × 10-10 mol/cm2, was consistent with that estimated from QCM. The adsorption rate of AQ-2-COOH on gold was, however, much slower than that on sil...

NEXAFS and XPS characterization of molecular oxygen adsorbed on Ni(100) at 80 K

X-ray photoelectron spectroscopy (XPS), thermal desorption spectroscopy (TDS) and near edge extended X-ray absorption fine structure (NEXAFS) have been combined to investigate the adsorption of oxygen on Ni(100) at 80 K. Three O(1s) XPS features were observed at 530.0, 531.1 and 534.7 eV when the Ni(100) surface was exposed to 600 L of oxygen at 80 K. They are assigned as O 2−, O 1− and molecular oxygen species, respectively. The presence of molecular oxygen has been confirmed by TDS and NEXAFS. Molecular O 2 on Ni(100) is oriented perpendicular to the surface, and the OO bond length is estimated to be 1.24 Å, based on the NEXAFS σ ∗ resonance energy.

Electronic and structural properties of Mn/Cu superstructures

We present a study of the growth of Mn/Cu/Mn/Cu slabs. The atomic short- and medium-range orders of the in situ grown multilayers have been investigated using x-ray photoelectron diffraction in the forward regime and low-energy electron diffraction techniques. Complementary results are given on the electronic structure and local magnetic moment by core level [x-ray photoelectron spectroscopy (XPS)], valence level (ultraviolet photoemission spectroscopy), and soft x-ray absorption measurements. The growth of copper overlayers on the $c(2\ifmmode\times\else\texttimes\fi{}2)\mathrm{M}\mathrm{n}/\mathrm{C}\mathrm{u}(100)$ system is found to be ordered, producing a fcc structure. We also show evidence on the growth of a second two-dimensional $c(2\ifmmode\times\else\texttimes\fi{}2)\mathrm{M}\mathrm{n}/\mathrm{C}\mathrm{u}$ alloy on top of the $p(1\ifmmode\times\else\texttimes\fi{}1)\mathrm{Cu}/c(2\ifmmode\times\else\texttimes\fi{}2)\mathrm{M}\mathrm{n}/\mathrm{C}\mathrm{u}(100)$ system, opening, therefore, the possibility of growing multilayers made of several $c(2\ifmmode\times\else\texttimes\fi{}2)\mathrm{Mn}/p(1\ifmmode\times\else\texttimes\fi{}1)\mathrm{Cu}$ units. The manganese atoms of the first and second two-dimensional magnetic alloys are found to be in a high-spin ground state in the Mn/Cu/Mn/Cu slabs and present the same XPS features, whereas the electronic structure investigated in the valence band shows slight differences.

Formation of an Sb–N compound during nitridation of InSb (001) substrates using atomic nitrogen

The effect of atomic nitrogen, generated by a radio frequency plasma source, on clean InSb(001) at 275 °C has been studied using x-ray photoelectron spectroscopy (XPS) and resonant Raman scattering (RRS). Chemically shifted XPS features of the Sb 3d region revealed the formation of a reacted Sb species. This reacted Sb was unambiguously identified as mainly Sb–N by comparison with results from as deposited and nitrided, thick elemental Sb layers on InSb. The Sb 3d feature due to this Sb–N species was found to have a chemical shift of 1.65±0.10 eV to higher binding energy compared with the InSb peak, while for the elemental Sb the shift was only 0.45±0.10 eV in the same direction. Although not obvious from the XPS data the RRS spectra of a much longer nitridation at 275 °C showed the presence of crystalline elemental Sb. Annealing studies of elemental Sb and nitrided Sb layers showed the Sb–N species to be significantly less volatile than elemental Sb.