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Chemical state

About: Chemical state is a research topic. Over the lifetime, 2378 publications have been published within this topic receiving 78183 citations.


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TL;DR: In this paper, the impact of doping on the structural, chemical states, optical properties and band gap nature of transition metal doped FeS2 thin films is investigated. But, the results are limited to a single sample.
Abstract: Transition metals doped FeS2 thin films are promising materials for optoelectronics, energy saving and storage applications. This is a first time report on the simultaneously Ni@Cu doped Fe1 – xMxS2 (M = Ni@Cu = 0, 2, 5, 10, and 20 at %) thin films fabricated by a simple chemical spray pyrolysis technique. In this paper we investigate the impact of doping on the structural, chemical states, optical properties and band gap nature by different characterization techniques. The SEM results show that surface morphology and granular grain size changes with the increment of Ni@Cu content which are coherent with the XRD results. The EDX and XPS measurements exhibit that the films are composed of Fe, S, Ni, and Cu elements whilst the films were slightly oxidized due to processing in the atmospheric conditions. Spectroscopy ellipsometry (SE) analysis demonstrates that the indirect band gap gradually increased from 1.38 eV (FeS2) to 1.64 eV (Ni@Cu = 10 at %) while at higher doping the band gap was decreased to 1.53 could be due to incomplete doping. So, the band gap of FeS2 can be tuned in between 1.38 and 1.64 eV by simultaneous Ni@Cu doping could be a suitable candidate for absorber application in solar cell devices. The other optical constants (dielectric constants, refractive index and extinction coefficient) explicitly carried out using SE measurement. Interestingly, progressing the absorption nature and bang gap in the visible region disclose a significant impact on the optical properties for optoelectronics applications.

2 citations

Journal ArticleDOI
TL;DR: In this paper, the bonding and chemical state of binary As-S glasses were investigated by determining the SKβ spectra with a vacuum 2-crystal X-ray spectrometer equipped with Ge(ll1) crystal analyzers.
Abstract: The bonding and chemical state of sulfur in binary As-S glasses were investigated by determining the SKβ spectra with a vacuum 2-crystal X-ray spectrometer equipped with Ge(ll1) crystal analyzers. For glasses with sulfur contents 60 at.%, the spectra became progressively similar to that of elemental sulfur with increasing sulfur content. It was found that S-S bonding occurs in the high-sulfur glasses.

2 citations

Journal ArticleDOI
TL;DR: In this article, surface atomic composition and chemical state were investigated for Si (100) bombarded with 5 keV ions (B+, C+, N+, O+, F+, Ne+).
Abstract: Surface atomic composition and chemical state have been investigated for Si (100) bombarded with 5 keV ions (B+, C+, N+, O+, F+, Ne+). The XPS observations reveal that the tendencies of surface chemical change by the irradiation are divided into three types. These are, 1) formation of monatomic layer composed of bombarding ions (B+, C+), 2) formation of new compounds between silicon and bombarding ions (N+, O+), and 3) no chemical change observed (F+, Ne+). The changes in surface atomic compositions are discussed in connection with irradiation-induced surface segre-gation of the implanted atoms and free energy (ΔG) or sublimation energy of the Si compounds.

2 citations

Journal ArticleDOI
TL;DR: Tantalum thin films of 35 nm thickness were investigated as diffusion barriers as well as adhesion-promoting layers between Cu and SiO2 using X-ray diffractometry (XRD), Scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and Xray photoelectron spectroscope (XPS) as discussed by the authors.
Abstract: Tantalum (Ta) thin films of 35 nm thickness were investigated as diffusion barriers as well as adhesion-promoting layers between Cu and SiO2 using X-ray diffractometry (XRD), Scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). After annealing at 600°C for 1h in vacuum, no evidence of interdiffusion was observed. However, XPS depth profiling indicates that elemental Si appears at the Ta/SiO2 interface after annealing. In-situ XPS studies show that the Ta/SiO2 interface was stable until 500°C, but about 32% of the interfacial SiO2 was reduced to elemental Si at 600°C. Upon cooling to room temperature, some elemental Si recombined to form SiO2 again, leaving only 6.5% elemental Si. Comparative studies on the interface chemical states of Cu/SiO2 and Ta/SiO2 indicate that the stability of the Cu/Ta/SiO2/Si system may be ascribed to the strong bonding of Ta and SiO2, due to the reduction of SiO2 through Ta oxide formation.

2 citations

Journal ArticleDOI
TL;DR: In this article, the chemical states of a Sb2Te3 thin film with the polycrystalline phase were investigated using high-resolution x-ray photoelectron spectroscopy with synchrotron radiation.
Abstract: We investigated chemical states of a Sb2Te3 thin film with the polycrystalline phase by using high-resolution x-ray photoelectron spectroscopy with synchrotron radiation. The Sb2Te3 thin film was formed by sputtering. The rhombohedral phase was confirmed by x-ray diffraction. To remove the surface oxide, we performed Ne+ ion sputtering for 1 hour with the beam energy of 1 kV and post-annealing at 100oC for 5 min in ultra-high vacuum. We obtained the Te and Sb 4d core-levels spectra with the peaks at the binding energies of 40.4 and 33.0 eV, respectively. The full-width of half maximum of both the Te and Sb 4d 5/2 core-levels is 0.9 eV. The Te and Sb core-levels only show a single chemical state, and we also confirmed the stoichiometry of approximately 2:3.

2 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202326
202249
202184
202089
201987
201894