Cu 2p core level photoemission for (a) Au, (b) Ag, and (c) Pd samples. A peak shift towards lower binding energies is observed for the Pd samples, indicating the lowering of the SBH. A high binding energy shoulder due to CuO can be observed. All spectra have been corrected for charging by using the adventitious C1s peak.
Illustration of method to determine the SBH from the XPS data from the valence-band spectra (right) and Cu 2p core level spectra (left) of (a) bare Cu2O film and (b) Cu2O film with 2 nm Au overlayer. The Fermi level is calibrated using the Fermi edge of Au. All spectra have been corrected for charging by using the adventitious C 1s peak.
Photoemission from metallic peaks of samples with 2 nm thick (a) Au, (b) Ag, and (c) Pd overlayers. A high binding energy shoulder due to PdO can be observed.
Contact resistivity is plotted against Cu2O nitrogen doping concentration for three contact metals: Au, Ag, and Pd.
Contact resistivity as a function of measurement temperature for Pd on Cu2O with three doping concentrations. Similar behavior (not shown) is also observed for Au and Ag samples. The solid black line represents a fit to a thermionic emission model; the dashed red and blue lines are guides to the eye.
Plot of the ratio kT/E 00 as a function of hole density (p) with m* = 0.58m 0 and ε = 7ε 0. The dashed line indicates that the ratio kT/E 00 = 1 and both thermionic emission and field effect processes are comparable. kT/E 00 for both undoped ([N] = 0.0 at. %, p = 3.7 × 1015 cm−3) and lightly ([N] = 0.6 at. %, p = 1.8 × 1018 cm−3) doped samples are indicated on the plot.
Contact resistivity as a function of measurement temperature for Cu, Ni, and Pd on highly doped ([N] = 1.2 at. %) samples. The dashed lines are guides to the eye.
Comparison of Schottky barrier heights obtained from XPS and CTLM.
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