Size-dependent melting of bi nanoparticles

2020-03-19 11:13:54

nm particles nanoparticles melting dependent

责任者: Olson, E.A.;Efremov, M.Yu.;Zhang, M.;Zhang, Z.;Allen, L.H. 单位: Dept. of Mater. Sci. & Eng., Univ. of Illinois, Urbana, IL, USA 来源出处: Journal of Applied Physics(J. Appl. Phys. (USA)),2005/02/01,97(3):34304-1 摘要: Nanocalorimetry was used to investigate the melting of Bi nanoparticles. The particles were formed by evaporating Bi onto a silicon nitride substrate, which was then heated. The particles self-assemble into truncated spherical particles. Below 5-nm average film thickness, mean particle sizes increased linearly with deposition thickness but increased rapidly for 10-nm-thick films. As expected, small particles were found to exhibit size-dependent melting temperatures less than the bulk melting temperature (e.g., ΔT=67 K for a 3-nm radius particle). The measured melting temperatures for particles below ~7 nm in radius, however, were ~50 K above the value predicted by the homogeneous melting model. We discuss this discrepancy in terms of a possible size-dependent crystal structure change and the superheating of the solid phase 关键词: bismuth;calorimetry;heat transfer;melting;nanoparticles;particle size;size dependent melting;Bi nanoparticles;nanocalorimetry;silicon nitride substrate;evaporation;self-assembly;spherical particles;film thickness;particle sizes;crystal structure;superheating;5 nm;10 nm;67 K;3 nm;7 nm;50 K;Bi;SiN