Electronic and atomic structure of the6H−SiC(0001¯)surface studied by ARPES, LEED, and XPS

Abstract

We present an investigation of the electronic and geometric structure of the carbon terminated 6H-SiC(0001) surface. The samples were prepared in different ways that result in the same unreconstructed (1ϫ1) surface. From angle-resolved photoemission spectra taken along the ⌫ M and the ⌫ K azimuth, the strong dispersion of a surface state in the ionic gap and of a bulk state at the boundary of the ionic gap is measured. This indicates unambiguously that large areas of the surface are well ordered. The comparison with band-structure calculations shows that even these areas do not have the properties of an intrinsic 6H-SiC(0001) surface. From a low-energy electron diffraction ͑LEED͒ structure analysis of the same surface a model is determined with domains of all three possible bilayer truncations of the bulk unit cell present at the surface with equal weight. For the well-ordered parts of the surface the combination of LEED and core-level x-ray photoemission spectroscopy ͑XPS͒ favors a geometry with hydrogen adatoms bonded to the topmost carbon atoms of the first bilayer thus saturating the surface dangling bonds. However, the XPS data also show that the applied sample treatment does not yield a surface that is completely free of oxygen contamination, which must be located in the disordered parts of the surface. ͓S0163-1829͑98͒11031-7͔

Photocatalytic Cleavage of Self‐Assembled Organic Monolayers by UV‐Induced Charge Transfer from GaN Substrates

“…OH‐terminated SiC was achieved by 5 min oxygen plasma treatment followed by etching for 5min in 5% HF, and then repeating the process. This has previously been reported to lead to surface hydroxylation 28–30 and was confirmed by XPS, FTIR and SWCA.…”

HREELS, STM, and LEED studies of theSi(100)−c(4×4)surface at 100 andHossain1, Kato2, Kawai3 2006Phys. Rev. B5110View full textAdd to dashboardCite

“…Referring to the lower C 1s BE of the C atom on the clean diamond surface compared with that of bulk diamond, 58 the Si-C dimer ͓Fig. 5͑e͔͒ is expected to result in the C 1s peak at lower BE than that of bulk SiC, [55][56][57] as observed in Ref. 42.…”

“…Assuming the C 1s binding energy for bulk SiC at 282.4 eV, the C 1s peak observed at 282.8 eV for Si͑100͒−c͑4 ϫ 4͒ was ascribed to the subsurface C. 28,42,54 However, the actual C 1s binding energy for bulk SiC has been reported at 283.4-283.7 eV. [55][56][57] In the present model ͓Fig. 5͑e͔͒, the C atom in the buckled Si-C dimer is bonded to three Si atom and possess a dangling bond.…”

SiC SURFACE RECONSTRUCTION: RELEVANCY OF ATOMIC STRUCTURE FOR GROWTH TECHNOLOGY

“…LEED structure analyses of several such samples of different polytypes and polarity indeed determined the surface geometry to consist of unreconstructed SiC bilayers, however, covered by a submonolayer amount of oxygen or hydrogen statistically adsorbed on top of the topmost atoms of the bilayer. 15,[22][23][24][25][26] An improvement of this situation can be achieved by a hydrogen etching procedure similar to a typical preparation step used before epitaxial SiC growth experiments. 27,28 When the sample is annealed in a quartz tube (e.g.…”