STRUCTURE AND MORPHOLOGY OF THE AS-POLISHED DIAMOND(111)-1X1 SURFACE

We present an X-ray diffraction study of the polished, unreconstructed diamond(111) surface. By measuring the distribution of diffracted int ensities along the (hk) = (10) crystal truncation rod, we have determi ned the structure of the unreconstructed surface. We find that after h eating to 650 degrees C, the polished diamond(111)-(1 x 1) surface exh ibits a single-bond cleavage plane terminated by hydrogen atoms and, f or 15% of the surface area, by adsorbed oxygen, most likely in the for m of hydroxyl groups. We observe relaxations in the first layers, most notably a 3% contraction between the first and second bilayer. AFM re sults are presented that confirm the morphology found in X-ray analysi s. Medium-energy ion scattering was used to determine the oxygen cover age. (C) 1997 Elsevier Science B.V.