317 research outputs found
Surface Structure and Surface Kinetics of InN Grown by Plasma-Assisted Atomic Layer Epitaxy: A HREELS Study
The surface bonding configuration and kinetics of hydrogen desorption from InN grown by plasma-assisted atomic layer epitaxy have been investigated. High resolution electron energy loss spectra exhibited loss peaks assigned to a Fuchs–Kliewer surface phonon, N-N and N-H surface species. The surface N-N vibrations are attributed to surface defects. The observation of N-H but no In-Hsurface species suggested N-terminated InN. Isothermal desorption data were best fit by the first-order desorption kinetics with an activation energy of (0.88 ± 0.06) eV and pre-exponential factor of (1.5 ± 0.5) × 105 s−1
Graphene formation on SiC substrates
Graphene layers were created on both C and Si faces of semi-insulating,
on-axis, 4H- and 6H-SiC substrates. The process was performed under high vacuum
(<10-4 mbar) in a commercial chemical vapor deposition SiC reactor. A method
for H2 etching the on-axis sub-strates was developed to produce surface steps
with heights of 0.5 nm on the Si-face and 1.0 to 1.5 nm on the C-face for each
polytype. A process was developed to form graphene on the substrates
immediately after H2 etching and Raman spectroscopy of these samples confirmed
the formation of graphene. The morphology of the graphene is described. For
both faces, the underlying substrate morphology was significantly modified
during graphene formation; sur-face steps were up to 15 nm high and the uniform
step morphology was sometimes lost. Mo-bilities and sheet carrier
concentrations derived from Hall Effect measurements on large area (16 mm
square) and small area (2 and 10 um square) samples are presented and shown to
compare favorably to recent reports.Comment: European Conference on Silicon Carbide and Related Materials 2008
(ECSCRM '08), 4 pages, 4 figure
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