Pk. Baumann et Rj. Nemanich, CHARACTERIZATION OF COBALT-DIAMOND(100) INTERFACES - ELECTRON-AFFINITY AND SCHOTTKY-BARRIER, Applied surface science, 104, 1996, pp. 267-273
Citations number
26
Categorie Soggetti
Physics, Condensed Matter","Chemistry Physical","Materials Science, Coatings & Films
UV photoemission measurements were used to relate the electron affinit
y and Schottky barrier of thin Co layers on diamond (100) surfaces. Co
balt films of 2 Angstrom thickness were deposited on natural single cr
ystal diamond (100) substrates by hot filament evaporation in ultra-hi
gh vacuum (UHV). The surfaces were characterized with auger electron s
pectroscopy and atomic force microscopy. The study explores the proper
ties of the cobalt-diamond interface as a function of different surfac
e cleaning procedures. Prior to deposition the diamond samples have be
en cleaned by UHV anneals at either 500 degrees C or 1150 degrees C. F
ollowing either of these anneals a positive electron affinity was dedu
ced from the ultraviolet photoemission measurements. The measurements
indicate that the surface annealed at 500 degrees C is terminated with
oxygen while the surface annealed at high temperature is free of adso
rbates. Upon deposition of Co on the surface heated to 1150 degrees C,
a negative electron affinity (NEA) was detected, and a Schottky barri
er height of 0.35 eV was measured. However, for Co films deposited on
substrates annealed to 500 degrees C a positive electron affinity and
a Schottky barrier height of 1.45 eV were observed. The results are di
scussed in terms of a model that relates the electron affinity to the
metal workfunction and the Schottky barrier.