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The size dependent melting is presented. As the size of the nanoparticles increases, the variation of the melting point becomes more monotonic and the temperature range of bistability shifts to higher temperatures. In large nanoparticles, the proportion of interior atoms increases and the average potential energy per atom converges to the bulk or thin films. | Communications in Physics, Vol. 24, No. 3 (2014), pp. 207-215 DOI:10.15625/0868-3166/24/3/4070 SIZE DEPENDENT MELTING OF SILICON NANOPARTICLES NGUYEN THI THUY HANG Department of Applied Physics, Ho Chi Minh University of Technology, Vietnam National University of Ho Chi Minh City E-mail: hangthuynguyen2001@yahoo.com Received 30 May 2014 Accepted for publication 21 August 2014 Abstract. Melting of crystalline silicon nanoparticles is studied by molecular dynamics (MD) simulations using StillingerWeber potential. Models are heated up from a crystalline to a normal liquid state. Temperature dependence of total energy and the Lindemann ratio exhibit a first-order-like behavior of the transition at the melting point. Heat capacity of the system presents a single peak at around the melting point. The size dependent melting is presented. As the size of the nanoparticles increases, the variation of the melting point becomes more monotonic and the temperature range of bistability shifts to higher temperatures. In large nanoparticles, the proportion of interior atoms increases and the average potential energy per atom converges to the bulk or thin films. Keywords: thermodynamics of melting, molecular dynamics simulations, size dependent melting, silicon nanoparticles. I. INTRODUCTION Melting of crystalline nanoparticles has been under much attention for a long time due to the scientific and technological importance of the phenomenon [1]. Since Takagi first reported the size dependent melting temperature of small particles by means of transmission electron microscope [2], researchers have paid more attention to this basic but still unclear phenomenon [3–6]. Now it is found that the melting temperature of metallic [3, 4], organic [6] and semiconductors [5] nanoparticles decreases with decreasing their particle size. In particular, silicon nanoparticles are interesting because the poor optical characteristics of silicon due to its indirect band structure are drastically .
