2, Sandia National Laboratories, Livermore, California, United States
Grain boundaries play an important role on the efficiency of CdTe solar cells since they can act as recombination centers for carriers. Experiments found in the literature show that different types of grain boundaries form during the growth of polycrystalline CdTe. However, little information about the dynamics of grain boundary growth and evolution has been reported. Investigating the dynamics of grain boundary growth and evolution at the atomic scale is difficult to achieve through experiments. On the other hand, computer simulations such as Molecular Dynamics (MD) allow to study the fundamental mechanisms of growth and evolution of grain boundaries. In this work, we apply MD simulations to study the fundamental mechanisms for the migration of Σ7 and Σ11 grain boundaries in CdTe. Differential energies are systematically applied to grains to study grain boundary motion at various temperatures. Our results show the presence of full and partial dislocations at the grain boundary. This suggests that dislocations play an important role in the migration of grain boundaries. These results will add to the understanding of grain boundary migration and the fabrication of higher quality CdTe-based materials to increase the solar cell efficiency.