Molecular Dynamics Modeling of Hydrogen in Silicon

Hydrogen-defect and hydrogen-impurity interactions determine the efficiency of passivation processes in solar cells. These interactions are investigated theoretically at (and near) the abinitio level using a variety of tools. The hydrogen-vacancy studies started with H-monovacancy interactions. Ongoing work deals with the clustering of vacancies and will continue with the interactions between Hand the most stable vacancy aggregates. The results discussed in the present paper deal with a remarkably stable and elecrically/optically inactive defect, the ring-hexavacancy. As for hydrogen-impurity interactions, the current effort focuses on the role of O and H-enhanced difffusion of O. These interactions are the likely reson why the hydrogenation of O-rich material does not lead to anincrease in the efficiency of the device.