Orientation‐Controlled Growth of Single‐Crystal Silicon‐Nanowire Arrays

Abstract

is higher than that observed for Co 3 O 4 with an average particle size of 20 nm (25 K). [11] This is in accordance with the smaller average particle size, which corresponds to a higher fraction of surface spins, and hence for which bulk behavior is expected to occur at higher temperatures. Relationships between block temperature and particle size have also been studied for Mn 3 O 4 and c-Fe 2 O 3 , and the peak temperature was also found to increase with decreasing particle size.[12]In conclusion, mesostructured Co 3 O 4 with Ia3d symmetry has been nanocast from cubic Ia3d mesoporous vinylsilica. The vinyl groups play an important role in entrapping Co(NO 3 ) 2 inside the pores. This process seems to be extendable to other metal oxides. The cobalt oxide synthesized has interesting magnetic properties, and may be the basis of magnetic nanocomposites, if the pore system can be filled with another ferromagnetic material. It will be very interesting to see what kind of magnetic properties result from the interaction of two different, ordered, ferromagnetic structures on a nanometer size scale.Experimental 0.5 g of vinyl-functionalized silica (synthesized using 20 % vinyltriethoxysilane and aged at 100 C [4], hereafter called vinylsilica) was soaked in 5 mL of 0.8 M Co(NO 3 ) 2 ethanolic solution, dried at 200 C, re-impregnated, and then calcinated at 450 C for 6 h. The amount of cobalt oxide in the composite was then typically 50± 55 wt.-%. The silica was then dissolved in a 2 M NaOH aqueous solution, with the NaOH solution being replaced 3 times. The samples were characterized using standard techniques, such as XRD, N 2 sorption analysis, and TEM. The magnetic properties were measured using a superconducting quantum interference device (SQUID). Orientation-Controlled Growth of Single-Crystal Silicon-Nanowire Arrays** By Shuaiping Ge, Kaili Jiang,* Xiaoxiang Lu, Yaofeng Chen, Rongming Wang, and Shoushan Fan* Development in the integrated-circuit (IC) industry is directed towards creating smaller and faster components that consume less power.[1] Owing to their unique structures and properties, one-dimensional nanoscale objects have shown many promising potential applications in future nanoscale electronics [2±4] and photonics applications. [2,5,6] Since the IC industry is currently dominated by silicon-based devices, silicon nanowires (SiNWs) will have the advantage of technical compatibility, compared with other semiconducting nanowires. Recently, many efforts have been directed towards the growth of SiNWs. [7,8] However, most of these methods give

Deflection induced cellular focal adhesion and anisotropic growth on vertically aligned silicon nanowires with differing elasticity

“…21,22 By increasing the temperature of substrates, the Au thin film on the Si(111) wafer starts to randomly crack and then evaporate, migrating from the wafer and forming liquid-phase Au nanodroplets of various sizes. This cracking allows Au to be randomly deposited onto a Si(111) wafer and diffuse over the substrate by the two well-known mechanisms of coalescence and Ostwald ripening.…”

Self-assembled and ordered growth of silicon and germanium nanowires

“…On silicon, in contrast to our results, they did not get any epitaxially grown wires whereas on GaAs, they got growth in 110 direction. They assume to have a certain amount of As/Ga dissolved in Au at the initial state of growth and thus incorporation of these species into the nanowire which could result in Ge et al [12] found that supersaturation could be a reason for the growth of silicon nanowires on silicon (111) once vertically and under certain conditions along the other 111 directions.…”

Metal-assisted chemical etching of silicon and the behavior of nanoscale silicon materials as Li-ion battery anodes

“…MAC etching used in conjunction with various film patterning techniques has been demonstrated as a promising method for Si NW fabrication [80]. The orientation-controlled growth of Si NW arrays [106,107] and the controlled growth of Si NWs in predetermined configurations [108] have been illustrated. Ultrathin anodic aluminum oxide (AAO) membranes have been utilized as versatile masks for fabricating 2D extended arrays of various functional nanostructures (microelectronics, optoelectronics, and sensing) [109] because of their unique ability to control the pore size and pore density.…”