Asymmetric distribution of surface second harmonic generation for thin silver films deposited on Si(111)
Department of Electrical Engineering, National Tsing Hua University, Hsin Chu, Taiwan
2 Department of physics, National Tsing Hua University, Hsin Chu, Taiwan
Corresponding author: a email@example.com
Published online: 18 August 2005
The asymmetric distributions of surface optical second harmonic generation (SHG) through azimuthally angular scans of (111) silicon wafers on which thin silver films were deposited, have been detected with different polarizations of output beams. On account of the inversion symmetry of silicon crystals, the SHG for the Ag/Si system is mainly contributed by the silver film and the silicon surface. In this work, we found that the interface strain implies an asymmetric intensity variation of SHG with respect to the surface azimuthal angles as an ultra thin Ag film is deposited on silicon wafers. This asymmetric behavior is prominent as the deposited silver layer is heated so that the continuous film aggregates to become granular nanoparticles. Similar changes of the surface asymmetric SHG are observed for a bare Si wafer imposed upon by an external force.
PACS: 78.67.Bf – Nanocrystals and nanoparticles / 42.65.Ky – Frequency conversion; harmonic generation, including higher-order harmonic generation / 61.25.Mv – Liquid metals and alloys
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2005