Effects of visible and synchrotron x-ray radiation on the growth of silver nanoplates on n-GaAs wafers:: A comparative study

A simple and effective approach has been developed to grow silver (Ag) nanoplates on n-type gallium arsenide (GaAs) wafers through a reaction between the wafers themselves and aqueous solutions of silver nitrate at room temperature [Sun and Wiederrecht, Small 3, 1964 (2007)]. In this letter, the effect of green laser irradiation, which can efficiently excite the valence band of a GaAs substrate to form electron-hole pairs in the shallow surface region (<3 mu m), on the growth of Ag nanoplates is studied. Illumination with the laser significantly depresses the growth of Ag nanoplates. In comparison, the influence of synchrotron x-rays, which can excite the deep core levels of elements and deeply penetrate (>50 mu m) into GaAs lattices, on the growth of Ag nanoplates is also studied. The results indicate that the excited deep core levels can relax into electron-hole pairs in the band edges to induce similar effects to that of the green laser except that the larger area around the x-ray beam is affected to inhibit the growth of Ag nanoplates. (C) 2008 American Institute of Physics.