Top edge facet development in asymmetric grooves

Top edge facet development in asymmetric grooves

The low pressure (20 mbar) organometallic vapour phase epitaxy (LP-OMVPE) of GaAs/GalnP in asymmetric grooves, patterned on (111)B GaAs substrates, has been examined. One of the characteristic features of this deposition is that facets develop along the top edges where the side wall planes meet the top surface. The origin of small facets at the top edge appears to be due to pre-growth condition...

Flat-surface, step-edge, facet–facet, and facet–step diffusion barriers in growth of a Pb mesa

0039-6028/$ see front matter 2008 Elsevier B.V. A doi:10.1016/j.susc.2008.05.009 * Corresponding author. Present address: IPRT Department of Energy, 307D Wilhelm Hall, Ames, IA E-mail address: [email protected] (Y. Han) We obtain important energy parameters for understanding growth kinetics of a faceted Pb mesa. Specifically, extensive calculations of diffusion barriers are performed for a...

Top driven asymmetric mantle convection

The role of decoupling in the low-velocity zone is crucial for understanding plate tectonics and mantle convection. Mantle convection models fail to integrate plate kinematics and thermodynamics of the mantle. In a first gross estimate, we computed at about 306 km/yr the volume of the plates lost along subduction zones. Mass balance predicts that slabs are compensated by broad passive upwelling...

On vector quantization for fast facet edge detection

Random-Edge Is Slower Than Random-Facet on Abstract Cubes

Random-Edge and Random-Facet are two very natural randomized pivoting rules for the simplex algorithm. The behavior of Random-Facet is fairly well understood. It performs an expected sub-exponential number of pivoting steps on any linear program, or more generally, on any Acyclic Unique Sink Orientation (AUSO) of an arbitrary polytope, making it the fastest known pivoting rule for the simplex a...