SPring-8, the large synchrotron radiation facility

Date & Time: February 25, 2005, 13:30-14:30

Speaker: Prof. Tom Tiedje
Affiliation: Electrical and Computer Engineering University of British Columbia

Abstract
　　Studies of surface shape evolution during MBE growth on patterned GaAs substrates have led to an understanding of how substrate topography can be used to control the migration of deposited adatoms in homoepitaxy ^[1]. In-situ light scattering measurements and ex-situ atomic force microscopy experiments on flat and patterned GaAs surfaces, show that adatoms respond to surface slopes as if there were an anti-Ehrlich-Schwoebel potential barrier at step edges which drives adatoms downhill. Using this concept we are able to predict the evolution of the shape of patterned GaAs (100) surfaces during growth for surface slopes up to about 30 degrees ^[2]. In addition we can express the coefficients of the continuum growth equation for GaAs, analogous to the KPZ equation, in terms of atomistic parameters for the adatom dynamics.

1. A. Ballestad et al. J. Cryst. Growth 271, 13 (2004)
2. A. Ballestad et al. Phys. Rev. Lett. 93, 159604 (2004)