Formation of Icosahedral Si Quantum Dots from Liquid Droplets

Kengo Nishio, Tetsuya Morishita, Wataru Shinoda, and Masuhiro Mikami

Phys. Rev. B 72 245321 (2005).

The present paper reports on molecular-dynamics simulations of the formation process of Si quantum dots (Si QDs). Icosahedral Si QDs are formed spontaneously by freezing 274-, 280- and 323-atom Si droplets. We find that the initialization of pentagonal channels leads into the overall icosahedral structure. We also study the melting behavior of the 280-atom icosahedral Si QD. We find that the melting point is reduced more than 15 % compared with that of bulk Si. A possible approach to synthesize icosahedral Si QDs is discussed. The formation of the icosahedral structure could be expected in other systems characterized by tetrahedral bonding network.

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