Surface properties of Cr2O3

Abstract

Thin (<5 nm) air-oxidized Cr layers are deposited on the alumina output windows of radio-frequency klystron tubes to prevent electron multipactor by reducing the secondary electron emission yield of the alumina surface. The top several nanometers of these layers appear to be Cr2O3. To compare the measured surface properties of these layers with those of clean stoichiometric Cr2O3, quasibulk Cr2O3 layers were produced by wet-H2-firing magnetron-deposited Cr films on Cu substrates and characterized by x-ray photoelectron-, Auger electron-, and electron energy loss spectra and secondary electron emission yield measurements. Other properties measured were x-ray diffraction structure, sheet resistance, and optical reflectivity. In particular, the peak of the secondary electron yield was found to be ∼1.7, which is considerably higher than the <1 yield value reported earlier in the literature. The Cr2O3 Cr 2p x-ray photoelectron core level spectrum was curve-fit using Doniach–Sunjic line shapes and statistical fitting methods. It is shown that each 2p level is composed of three multiplet-split peaks 1.1 eV apart. In addition, the three 2p1/2 peaks are folded with a 2p3/2 3d satellite.

A Comparative Study of Cr2O3 Thin Films Obtained by MOCVD using Three Different Precursors

“…Films of Cr 2 O 3 have been made by a variety of methods including evaporation [4] or sputtering [1] of oxides, oxidation of chromium metal, [5,6] electrochemical deposition, [7] spray pyrolysis, [8] and dip-coating [9] . One problem in the deposition of such films is retention of stoichiometry as, particularly with physical methods, substoichiometric oxides are formed.…”

Effect of crystallinity of Co layer on perpendicular exchange bias in Au-capped ultrathin Co film on Cr2O3(0001) thin film

“…Moreover, the XP spectra are reproduced by two mixed Lorentz/Gaussian functions, as shown by thin solid lines. The peak at the binding energy of metallic Cr (574.1-574.8 eV [21,22]) is not observed, showing that no metallic Cr is present in our Cr 2 O 3 layer. In the XP spectra of O 2 À , a single peak at 531.1 eV is observed, which is well fitted by mixed Lorentz/Gaussian functions.…”

“…4(a), two peaks are observed at 577.1 and 586.6 eV. The binding energies are in the range of the literature values for Cr2p 3/2 and Cr2p 1/2 in Cr 2 O 3 [21,22]. Moreover, the XP spectra are reproduced by two mixed Lorentz/Gaussian functions, as shown by thin solid lines.…”

“…In the XP spectra of O 2 À , a single peak at 531.1 eV is observed, which is well fitted by mixed Lorentz/Gaussian functions. The observed peak is near the binding energy of O1s in oxides [21,22]. The valence states of the Cr and O ions also indicate that no other oxide phase or metallic Cr is included in our Cr 2 O 3 layer.…”

Artifacts in Secondary Electron Emission Yield Measurements

“…TiN continues to be used widely today to coat beam chambers (particularly Al) and high-rf field components. Other coatings have been evaluated and found successful as well, e.g., Cr 2 O 3 for ceramics [3] and TiZrV non-evaporable getter for metals [4].…”