Ni K‐edge XAFS analysis of NiO thin film with multiple scattering theory

Abstract

a Nickel oxide is a p-type semiconductor with wide band gaps of 3-4 eV. The defects of O or Ni atoms are essential to explain some specific features of the semiconductors. The information of the local structure around Ni is important to clarify the conduction mechanism. We investigate the Ni K-edge X-ray absorption fine structure spectra of the nickel oxide thin films in order to obtain the structural information around Ni. For the X-ray absorption near edge structure (XANES) analyses, we apply a full multiple scattering theory. The experimental results suggest that the crystallinity of the thin films depends on the annealing temperature. The distances of Ni-O and Ni-Ni are 1.984 and 2.747 Å for the sample annealed at 100°C and 2.084 and 2.947 Å for the sample annealed at 300°C, respectively. Our multiple scattering calculations can satisfactorily explain the experimental result.

Plasmonic Ag nanoparticles arbitrated enhanced photodetection in p-NiO/n-rGO heterojunction for future self-powered UV photodetectors

“…The pre-edge structure rises from 1s to 3d states (electronic transition), which confirms the presence of Ni. One can notice that the pre-edge peak 'A' at ∼8333 eV (figure5(a)) was considered to possess direct dipole transition from Ni 1s states to O 2p states, owing to the effective hybridization as reported in earlier literature[49]. The EXAFS oscillations were analyzed through the earlier-mentioned standard procedure[48].The EXAFS data k 2 χ(k) and its corresponding Fourier transforms are depicted in figures 5(b), (c).…”

Dynamic restructuring of nickel sulfides for electrocatalytic hydrogen evolution reaction

“…The corresponding results of fitting at +1.00 V were shown in Supplementary Table 4, and the Ni-O show a bond length of ∼2.00 Å. Highly crystalline NiO has a characteristic Ni-O distances around 2.09 Å; however, the short-range order in NiO reveals that the Ni-O distances for amorphous and/or nanocrystalline NiO may decrease to 2.00-2.06 Å 43,44 . This result further confirms the formed NiO is in the form of a very small cluster.…”

X-ray and Nuclear Spectroscopies to Reveal the Element-Specific Oxidation States and Electronic Spin States for Nanoparticulated Manganese Cyanidoferrates and Analogs

“…Nevertheless, it appears to be very meaningful to use modern spectroscopies [26][27][28][29][30][31][32][33][34][35] to shed some light directly on these issues which are also critical for evaluating its suitability as an MRI agent [19,20].…”

“…SR-based X-ray absorption spectroscopy (abbreviated as XAS hereafter, Figure 1c) measures the electronic transition from a core shell to a valence shell. As XAS is sensitive to valence electrons and is element specific (related to core shell) at the same time, it is one of the best methods for investigating the oxidation state of a specific element in different chemical compounds or enzymes [27,[29][30][31][32]36,37]. For the 3d transition-metal ions (e.g., Mn, Co or Fe ion), K-edge XAS uses a hard X-ray beam of >4000 eV to study the transitions of 1s → 3d, → 4p and → continuum (Figure 1c, the transition designated by the dashed blue line).…”

“…For the 3d transition-metal ions (e.g., Mn, Co or Fe ion), K-edge XAS uses a hard X-ray beam of >4000 eV to study the transitions of 1s → 3d, → 4p and → continuum (Figure 1c, the transition designated by the dashed blue line). Although the information obtained from the K-edge XAS seems comprehensive [27,[32][33][34]37], L-edge XAS [29][30][31]36,38,39] (Figure 1c, the transition designated by the solid red line) as well as L-edge RIXS or L-edge X-ray emission spectroscopy [40][41][42][43] have several advantages over the K-edge XAS for studying electronic structures such as oxidation states and spin states. These advantages include a direct probe of the ligand-metal bonding orbital (3d); a dipole-allowed 2p → 3d transition (vs. 1s → 3d in K-edge XAS); a better energy resolution (e.g., 0.1 eV vs. 1 eV); and a rich spectral multiplet which is specific to particular electronic structures and coordination environments [29][30][31]36,38,39].…”