Date of Graduation

1990

Document Type

Dissertation/Thesis

Abstract

The growth of iron up to several monolayers in thickness on Cu(100), Cu(111) and Cu(110) are studied using the combined techniques of AES and EELS. The graphs of the Auger peak-to peak-height of iron and copper as a function of iron thickness do not clearly show the linear segment which is the indication of the layer growth. The results from EELS indicate that the fcc iron formed first and then some bcc iron is formed on the top of this fcc iron. The critical thicknesses for the indication of bcc iron are 13 ML for Cu(100), 3 ML for Cu(111) and 1 ML for Cu(110). After iron deposition, the reaction with CO/H{dollar}\\sb2{dollar} has been performed. The Auger spectra show a carbidic character and the EEL spectra indicate new peaks around 5.3 and 8.5 eV. They are assigned to transitions from C(2p)-Fe(3d) hybridised states to the states above the Fermi level. Another new peak at 14.9 eV is attributed to the transition from the C(2s) states to the states above the Fermi level. The intensity of the M{dollar}\\sb2{dollar} peak is remarkably reduced after reaction while the intensity of the M{dollar}\\sb3{dollar} peak is nearly the same as before the reaction. The sample compositions as a function of depth are determined using EELS by varying the primary energies of electrons. The thin oxide layer has been observed. The estimated thickness of the oxide layer is 4-5 A for the Ti/C multilayer and 3-5 A for silicon. Before sputtering, the carbon layer shows the graphitic behavior.

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