XPS study of Cu/substrate systems obtained by pulsed laser deposition

Abstract

In this paper XPS was used to study the evolution of Cu 2p 3/2 peaks with the increase of the metal coverage on different types of substrate: Ni, HOPG (highly orientated pyrolytic graphite) and KBr. The results showed that: (i) the binding energy of the Cu 2p 3/2 peak in the system Cu/HOPG decreases with surface coverage, while in the system Cu/Ni it increases; (ii) with the increase of the Cu coverage in all the systems studied a general trend of the Cu 2p 3/2 peak is the reduction of FWHM (full width at half maximum), but the degree of the FWHM change depends greatly on the type of the substrate. The results obtained for binding energy change are discussed in relation to the initial and final state contributions. The results indicate that the final state contributes more to the change of the binding energy in the more 3-dimensional structure Cu/HOPG system, while in the more 2-dimensional Cu/Ni system the initial state contribution dominates. The FWHM change is analysed in terms of the size distribution of clusters and change of the lifetime of the holes left by the photoelectrons, which is affected by the size of the clusters and the degree of the hybridization between the s and d electrons.

Positive XPS binding energy shift of supported CuN-clusters governed by initial state effects

“…been discussed in terms of a final state effect, contrary to our conclusion. However the correlation energy shift has been neglected in the Auger parameter analysis of Lai et al [16]. If we would neglect the correlation energy shift than the final state effect would indeed be stronger than the initial state effect as readily inferred from Fig.…”

“…1a. Lai et al [16] have measured a positive binding energy shift of atomic Cu-islands of various thicknesses on HOPG. This experimental observation, which is similar to ours, has Table 1 Binding energy shift BE (2p 3/2 ), Auger energy shift KE (peak maximum of L3M4,5M4,5) and Coulomb correlation energy shift of the 3d −2 Auger final state Ecorr [23] as derived from Ref.…”

“…The Auger parameter concept will be applied here to quantify the physical contributions to the observed XPS core level shifts of mass selected supported Cu N clusters. Note that a similar study has been done for atomic islands of Cu on HOPG and Ni disregarding the Coulomb correlation energy shift [16]. Table 1 shows the Auger parameter shift ˛ and core electron binding energy shift BE of the supported Cu N -clusters.…”

Core–Shell Nanostructured Hybrid of Nickel Hydroxide Supported on Copper Hydroxide Nanorod Arrays Used as Advanced Supercapacitors with High Efficiency and Ultraperformance

“…By comparing the XPS spectra of Cu(OH) 2 @Ni(OH) 2 with pure Cu(OH) 2 and Ni(OH) 2 , it can be found that the characteristic peak is shifted, which is due to the strong interaction between Cu(OH) 2 and Ni(OH) 2, leading to the shift of the binding energies of Cu and Ni in Cu(OH) 2 @Ni(OH) 2 . [26][27][28] The electrochemical behavior of Cu(OH) 2 @Ni(OH) 2 electrode using mercury oxide (HgO) as reference electrode was investigated in a three-electrode system with the potential window of 0-0.5 V in 6 m KOH. In the meantime, Cu(OH) 2 @ Ni(OH) 2 testing electrode has been characterized by SEM to confirm the operating status after a battery of cyclic voltammogram (CV), galvanostatic charge and discharge (GCD), and electrochemical impedance spectroscopy (EIS) measurements, and the corresponding digital images are displayed in Figure S1a,b (Supporting Information).…”

Characterization of laser‐treated Rene 41 surface due to B4C and SiC particles at surface prior to laser treatment

“…Considerable research studies were carried out to examine laser treatment of high‐performance nickel‐based alloys . Effect of heat treatment on microstructure and mechanical properties of laser‐treated Rene 41 was investigated by Li et al …”