Electric field dependent structural and vibrational properties of the Si(100)-H(2 x 1) surface and its implications for STM induced hydrogen desorption

SURFACE SCIENCE

卷:429

Article

Stokbro, K

关键词: ab initio quantum chemical methods and calculations;    adatoms;    field effect;    hydrogen;    low index single crystal surfaces;    semiconducting surfaces;    silicon;    tunneling;    vibrations of adsorbed molecules;   

DOI  :  10.1016/S0039-6028(99)00396-9

来源: Elsevier

【 摘 要 】

We report a first principles study of the structure and the vibrational properties of the Si(100)-H(2 x 1) surface in an electric field. The calculated vibrational parameters are used to model the vibrational modes in the presence of the electric field corresponding to a realistic scanning tunneling microscopy tip-surface geometry. We find that local one-phonon excitations have short lifetimes (10 ps at room temperature) due to incoherent lateral diffusion, while diffusion of local multi-phonon excitations are suppressed due to anharmonic frequency shifts and have much longer lifetimes (10 ns at room temperature). We calculate the implications for current induced desorption of H using a recently developed first principles model of electron inelastic scattering. The calculations show that inelastic scattering events with energy transfer n (h) over bar omega, where n>1, play an important role in the desorption process. (C) 1999 Elsevier Science B.V. All rights reserved.

【 授权许可】

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