Role of Surface Termination on Hot Electron Relaxation in Silicon Quantum Dots: A First-Principles Dynamics Simulation Study.
The role of surface termination on phonon-mediated relaxation of an excited electron in quantum dots was investigated using first-principles simulations. The surface terminations of a silicon quantum dot with hydrogen and fluorine atoms lead to distinctively different relaxation behaviors, and the fluorine termination shows a nontrivial relaxation process. The quantum confined electronic states are significantly affected by the surface of the quantum dot, and we find that a particular electronic state dictates the relaxation behavior through its infrequent coupling to neighboring electronic states. Dynamical fluctuation of this electronic state results in a slow shuttling behavior within the manifold of unoccupied electronic states, controlling the overall dynamics of the excited electron with its characteristic frequency of this shuttling behavior. The present work revealed a unique role of surface termination, dictating the hot electron relaxation process in quantum-confined systems in the way that has not been considered previously.
Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27514, United States.
Kyle G
KG
Reeves
Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign , Champaign, Illinois 61820, United States.
André
A
Schleife
Condensed Matter and Materials Division, Lawrence Livermore National Laboratory , Livermore, California 94550, United States.
Alfredo A
AA
Correa
Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27514, United States.
Yosuke
Y
Kanai
Fewest switches surface hopping; electron relaxation; quantum dots; silicon; surface passivation