Zinc – HarwellXPS Guru

The 3d band in zinc oxide (ZnO) is located relatively low, approximately 3 eV from the bottom of the valence O2p band. Some theoretical works even consider the 3d electrons as core electrons that are not involved in covalent bonding between zinc and oxygen.

The 4s and 4p states of zinc have significantly smaller ionization sections than the 3d and O2p states, by about two orders of magnitude, in the quantum energy range of 50-150 eV. This means that the photoemission intensity from the O2p-band is largely determined by the O2p and Zn3d states, which can affect the observed binding energy.(4)

Covalent Bonding

While some studies have considered Zn 3d electrons as core electrons, others suggest that Zn3d orbitals participate in covalent bonding with oxygen. This mixing of Zn3d and O2p states can influence the valence band and the intensity ratio of Zn3d and O2p bands, which could affect the binding energy.(4)

Experimental Advice

Zinc analysis is typically performed on the Zn 2p photoemission, however obtaining the Zn KLL auger region is often paramount for interpreting the data correctly. There may be a slight overlap between the Zn 2p peaks and the O and V KLL augers from Al X-rays, however it should not impede deconvolution, partly due to the large doublet separation (23 eV).

Fitting Advice

Common binding energies for Zinc species may be found below:

Species	Binding energy / eV	Charge Ref.	Ref.
Zn	1021.65	Au 4f / 83.95 eV	1
ZnO	1021.7	C 1s / 285 eV	2

Table 1: Zinc binding energies

While the separation above may be small, as mentioned previously, the Zn LMM auger may assist in spectral understanding via the modified Auger parameters (table 2).

Species	α‘ / eV	Ref
Zn	2014	3
ZnO	2009.8	3

Table 2: Modified auger parameters for Zinc species

Data acquired by HarwellXPS
Ramgir, N. S., et al. (2006). “ZnO multipods, submicron wires, and spherical structures and their unique field emission behavior.” The Journal of Physical Chemistry B 110(37): 18236-18242. Read it online here.
Diler, E., et al. (2014). “Initial formation of corrosion products on pure zinc and MgZn2 examinated by XPS.” Corrosion science 79: 83-88. Read it online here.
Leontiev, S. A., et al. “Detailed XPS and UPS studies of the band structure of zinc oxide.” Journal of structural chemistry 38 (1997): 725-731. Read it online here.

Initial vs Final State Effects

Multiplet Splitting

Multiplet splitting of s-orbitals in first row transition metals

Peak Asymmetry in Conducting Materials

Photoionisation Cross Sections

Spin-Orbit Splitting

The Auger, or Auger-Meitner, Process and Auger Peaks

Login to Your Account

Personal Details

Knowledge Base

Antimony