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Abstract: Appl. Phys. A 63, 533-47 (1996)


Nonlinear optical investigations of the dynamics of hydrogen interaction with silicon surfaces

U. Höfer
Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Str. 1, D-85740 Garching, Germany.

 

Abstract

Optical second-harmonic generation (SHG) from silicon surfaces may be resonantly enhanced by dangling-bond-derived surface states. The resulting high sensitivity to hydrogen adsorption combined with unique features of SHG as an optical probe was exploited to study various kinetical and dynamical aspects of the adsorption system H2/Si. Studies of surface diffusion of H/Si(111)7×7 and recombinative desorption of hydrogen from Si(111)7×7 and Si(100)2×1 revealed that the covalent nature of hydrogen bonding on silicon surfaces lead to high diffusion barriers and to desorption kinetics that strongly depend on the surface structure. Recently, dissociative adsorption of molecular hydrogen could be observed for the first time by heating Si(100) and Si(111) surfaces to temperatures between 550 K and 1050 K and monitoring the SH response during exposure to a high flux of H2 or D2. The measured initial sticking coefficients for a gas temperature of 300 K range from 2×10-9 to 1×10-5 and strongly increase as a function of surface temperature. These results demonstrate that the lattice degrees of freedom may play a decisive role in the reaction dynamics on semiconductor surfaces.

 

PACS: 42.65.Ky, 68.35.Ja, 82.65.My

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Zuletzt aktualisiert: 23.09.2010 · armbrusn

 
 
 
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