AVS 56th International Symposium & Exhibition
    Surface Science Thursday Sessions
       Session SS-ThP

Paper SS-ThP20
Degradation of Semiconductor Photoelectrode Surfaces in Aqueous Environments from ab-initio Molecular Dynamics

Thursday, November 12, 2009, 6:00 pm, Room Hall 3

Session: Surface Science Poster Session
Presenter: B. Wood, Lawrence Livermore National Laboratory
Authors: B. Wood, Lawrence Livermore National Laboratory
T. Ogitsu, Lawrence Livermore National Laboratory
E. Schwegler, Lawrence Livermore National Laboratory
Correspondent: Click to Email
Among currently known approaches for hydrogen production, catalytic splitting of water molecules using semiconductor-based photoelectrochemical (PEC) devices has garnered particular interest, with reasonably high efficiencies already demonstrated in laboratory conditions. Unfortunately, these materials often evidence extremely facile surface corrosion, severely limiting their practical use in real-world devices. Currently, a clear understanding of this corrosion process at the water-semiconductor interface and its damaging effect on catalytic activity is lacking. Although certain theoretical efforts have attempted to address this issue, these studies have generally focused on zero-temperature gas-phase molecular adsorption, forgoing a realistic model of the liquid-solid interface. Accordingly, we have performed extensive ab-initio molecular dynamics simulations to probe the structure, chemistry, and dynamics of the water-electrode interface for model semiconductor systems in a realistic aqueous environment. Our work has focused on InP and GaAs, which, although structurally and functionally similar, exhibit substantial differences in terms of stability in an aqueous environment and in surface reactivity. These calculations are able to provide a unique in-depth understanding of surface

structure and transport. As such, they promise to provide a crucial first step towards understanding the complexities of the atomistic processes involved in hydrogen evolution and PEC corrosion.