Formation and evolution of Au-SiOx Heterostructures: From nanoflowers to nanosprouts

Formation of nanoflowers: Au and Ni silicide cores surrounded by SiOx branches

“…Thus, Au-Si droplets and Ni silicide can form due to the easy interdiffusion of Au, Ni, and Si. Au/Si phase separation occurs during cooling [3,55], and Ni silicide may remain stable down to room temperature [41][42][43][44][45][46], finally forming particles with two contrasts. Besides, Ni may also diffuse into the Si substrate, leading to the formation of the Ni silicide, and a cross-sectional view of Ni silicide is given in Figure 4c based on reported works [44,48,56].…”

“…Substantial efforts have been devoted to developing different kinds of nanofabrication methods during the past decades. For example, silicon oxide (SiO x ) nanostructures can be grown by the catalyzing effect of Au nanoparticles based on the vapor-liquid-solid (VLS) mechanism [1][2][3][4]. Au-SiO x nanoflowers consisting of Au nanoparticles and surrounding SiO x nanowires (NWs) show a significant enhancement of the photoluminescence (PL) emission compared with pure SiO x NWs due to the coupling effect between the local surface plasmon resonance (LSPR) of Au nanoparticles and the PL emission of SiO x [2].…”

“…Similar Au-SiO x nanoflowers have also been obtained by depositing Au thin films on Si substrates with a thick silicon dioxide (SiO 2 ) layer and subsequent rapid heating in reducing atmosphere. Here, the Si vapor source is silicon monoxide (SiO) gas produced by the decomposition of the SiO 2 layer or the active oxidation of the Si substrate at higher temperatures in oxygen-deficient environment [3,4]. Another cost-effective nanofabrication method, thin film dewetting, driven by the reduction of the surface energy and the interface energy has also been profusely studied because it provides a straightforward and fast way to produce nanoparticles [5][6][7].…”

“…Apart from Au, both Ni and Ag can also catalyze the growth of NWs based on the VLS mechanism [26][27][28], and Si NWs have been grown using alloyed AuAg nanoparticles [29]. Au-SiO x nanoflowers have been fabricated by combining the dewetting of Au thin films and the growth of NWs based on the VLS mechanism [3,4]. This has inspired the possible fabrication of nanoflowers from multicomponent nanoparticles and surrounding SiO x NWs, on which, to date, there is no relevant research.…”

Nanoflowers: A New Approach of Enzyme Immobilization

“…The first studies in this area refer to nanometric flower-type structures synthesized by heating silicon compounds at high temperatures. [26,27] Many types of materials were studied later, such as copper ions, [15,28,29] gold, [30,31] zinc, [32] platinum [33] among others materials. The first synthesis of organicinorganic hybrid nanoflowers, as described by Ge, Lei, and Zare, [16] happened by accident when 20 μl of 120 mM CuSO 4 solution was added to 3 mL of phosphate-buffered saline (PBS) solution containing 0.1 mg mL À 1 bovine serum albumin (BSA) at pH 7.4 and 25 °C.…”