Synthesis of branched 'nanotrees' by controlled seeding of multiple branching events

Abstract

The formation of nanostructures with controlled size and morphology has been the focus of intensive research in recent years. Such nanostructures are important in the development of nanoscale devices and in the exploitation of the properties of nanomaterials. Here we show how tree-like nanostructures ('nanotrees') can be formed in a highly controlled way. The process involves the self-assembled growth of semiconductor nanowires via the vapour-liquid-solid growth mode. This bottom-up method uses initial seeding by catalytic nanoparticles to form the trunk, followed by the sequential seeding of branching structures. Each level of branching is controlled in terms of branch length, diameter and number, as well as chemical composition. We show, by high-resolution transmission electron microscopy, that the branching mechanism gives continuous crystalline (monolithic) structures throughout the extended and complex tree-like structures. The controlled seeding method that we report here has potential as a generic means of forming complex branching structures, and may also offer opportunities for applications, such as the mimicking of photosynthesis in nanotrees.

In situ etching for total control over axial and radial nanowire growth

“…Recently nanowires (NWs) have attracted attention as one of the most promising ways to combine highperformance Ⅲ-Ⅴ materials with new functionality [1][2][3][4] and existing Si technology [5,6]. An unintentional NW shell can harm device functionality by short circuiting axially designed components and by becoming a surrounding and competing recombination center [7] for charge carriers.…”

Photocurrent and photoconductance properties of a GaAs nanowire

“…[1][2][3][4][5][6][7][8][9][10] A very suitable and versatile technique for nanowire growth is the direct synthesis on a substrate. [11][12][13][14] The fabrication of III-V semiconductor nanowire based devices by such a bottom-up approach ensures the rational use of materials, as the nanowires can be obtained in principle on any substrate. Here, we report on the optoelectronic properties of photodetectors based on single p-doped GaAs nanowires grown by molecular beam epitaxy ͑MBE͒ with the so-called vapor-liquid-solid method using Ga droplets as self-catalysts.…”

Complex Nanostructures: Synthesis and Energetic Applications

“…The resulting nanostructures therefore tend to vary in morphologies. This approach has been applied to Si [22], GaP [28], PdSe [29], InAs [30] and indium tin oxide [31] nanostructures. In a slight variation, this strategy has also been applied to solution phase synthesis such as the solution-liquid-solid (SLS) growth [32].…”