Au and Ag nanoparticles embedded in amorphous Al2O3 matrix are fabricated by the pulsed laser deposition (PLD) method and rapid thermal annealing (RTA) technique, which are confirmed by the experimental high-resolution transmission electron microscope (HRTEM) results, respectively. The strain distribution of Au and Ag nanoparticles embedded in the Al2O3 matrix is investigated by the finite-element (FE) calculations. The simulation results clearly indicate that both the Au and Ag nanoparticles incur compressive strain by the Al2O3 matrix. However, the compressive strain existing on the Au nanoparticle is much weaker than that on the Ag nanoparticle. This phenomenon can be attributed to the reason that Young’s modulus of Au is larger than that of Ag. This different strain distribution of Au and Ag nanoparticles in the same host matrix may have a significant influence on the technological potential applications of the Au-Ag alloy nanoparticles. 1. Introduction The incorporation of multiple metals into a single system has induced intensive interest due to its promising applications. Therefore, the fabrication of alloy nanoparticles has become a major challenge. Particularly, Au-Ag alloy has been confirmed to be suitable for the application in surface plasmon absorption. These two noble metals have practically the same lattice constant and are chemically similar. Moreover, in the bulk phase they are miscible at all compositions. These properties provide the possibility to study the equal structures of different compositions without having to consider the influence of strong structural changes. By combining these two metals into a single entity, the catalytic performance of the material can be enhanced [1] and the surface plasmon absorption of Au-Ag alloy nanoparticles can be varied continuously between the absorptions of monometallic Au and Ag nanoparticles by changing the ratios of the precursors of Au and Ag [2]. On the other hand, nanocomposite films that consist of small metal nanoparticles embedded in metal oxides have attracted attention because they are expected to have many useful electronic and optical properties as a result of quantum size effects [3, 4]. These systems have useful applications in catalysis, photocatalysis, sensors, and novel optoelectronic devices. However, substantial compressive strain can be induced during the growth process of nanoparticles embedded in a host matrix. The strain may also have much influence on the microstructure and physical properties of nanoparticles [5, 6]. Therefore, in order to understand and control the
References
[1]
J.-H. Liu, A.-Q. Wang, Y.-S. Chi, H.-P. Lin, and C.-Y. Mou, “Synergistic effect in an Au-Ag alloy nanocatalyst: CO oxidation,” Journal of Physical Chemistry B, vol. 109, no. 1, pp. 40–43, 2005.
[2]
P. Mulvaney, “Surface plasmon spectroscopy of nanosized metal particles,” Langmuir, vol. 12, no. 3, pp. 788–800, 1996.
[3]
C. L. Yuan, P. S. Lee, and S. L. Ye, “Formation, photoluminescence and charge storage characteristics of Au nanocrystals embedded in amorphous Al2O3 matrix,” Europhysics Letters, vol. 80, no. 6, Article ID 67003, 2007.
[4]
X. F. Luo, C. L. Yuan, and Z. R. Zhang, “Synthesis, photoluminescence and charge storage characteristics of isolated silver nanocrystals embedded in Al2O3 gate dielectric,” Thin Solid Films, vol. 516, no. 21, pp. 7675–7679, 2008.
[5]
C. L. Yuan, S. L. Ye, B. Xu, and W. Lei, “Strain induced tetragonal SrTiO3 nanoparticles at room temperature,” Applied Physics Letters, vol. 101, no. 7, Article ID 071909, 2012.
[6]
C. L. Yuan, Q. Liu, and B. Xu, “Strain-induced structural phase transition of Si nanoparticles,” Journal of Physical Chemistry C, vol. 115, no. 33, pp. 16374–16377, 2011.
[7]
K. H. Huebner, D. L. Dewhirst, D. E. Smith, and T. G. Byrom, The Finite Element Method for Engineers, John Wiley & Sons, New York, NY, USA, 2001.
[8]
J. Gr？nqvist, N. S？ndergaard, F. Boxberg, T. Guhr, S. ？berg, and H. Q. Xu, “Strain in semiconductor core-shell nanowires,” Journal of Applied Physics, vol. 106, no. 5, Article ID 053508, 2009.
[9]
D. Barettin, S. Madsen, B. Lassen, and M. Willatzen, “Comparison of wurtzite atomistic and piezoelectric continuum strain models: implications for the electronic band structure,” Superlattices and Microstructures, vol. 47, no. 1, pp. 134–138, 2010.
[10]
C. L. Johnson, E. Snoeck, M. Ezcurdia et al., “Effects of elastic anisotropy on strain distributions in decahedral gold nanoparticles,” Nature Materials, vol. 7, no. 2, pp. 120–124, 2008.
[11]
Z. W. Shan, G. Adesso, A. Cabot et al., “Ultrahigh stress and strain in hierarchically structured hollow nanoparticles,” Nature Materials, vol. 7, no. 12, pp. 947–952, 2008.
[12]
L. T. Sun, A. V. Krasheninnikov, T. Ahlgren, K. Nordlund, and F. Banhart, “Plastic deformation of single nanometer-sized crystals,” Physical Review Letters, vol. 101, no. 15, Article ID 156101, 2008.
[13]
M. F. Ashby and D. R. H. Jones, Engineering Materials, vol. 1, Pergamon, Oxford, UK, 1980.
[14]
H. Hofmeister, M. Dubiel, H. Goj, and S. Thiel, “Microstructural investigation of colloidal silver embedded in glass,” Journal of Microscopy, vol. 177, no. 3, pp. 331–336, 1995.
[15]
V. V. Voronkov and R. Falster, “Strain-induced transformation of amorphous spherical precipitates into platelets: application to oxide particles in silicon,” Journal of Applied Physics, vol. 89, no. 11, pp. 5965–5971, 2001.
