Original Anisotropic Growth Mode of Copper Nanorods by Vapor Phase Deposition

Abstract

We report on a thermal evaporation method to synthesize copper nanorods, up to several microns long. The synthesis parameters that control the size and aspect ratio are studied to understand their influence on this anisotropic growth mode. We exploit the multifunctionalities of electron microscopy for studying the structural properties of these nanorods, in particular their growth morphology. By analyzing the face-centered cubic structure of the nanorods along several orientations, we demonstrate that their anisotropic axis is parallel to the [110] direction. The precise 3D shape of the nanorods is determined by using electron tomography, evidencing a morphology with a 2-fold symmetry and rectangular facets. This unusual faceting for metal nanorods is actually consistent with energetic considerations and arises from a growth mode that is different from the one of chemically prepared nanorods.

In Situ Investigation of Defect-Free Copper Nanowire Growth

“…The nucleation dynamic models indicate that catalytic interfaces, typical dislocations (twin structures, edge, and screw dislocations), and other defects are necessary to decrease the nucleation barrier for the anisotropic nucleation of nanowire growth. − In other words, typical dislocations and defect conditions play a critical role in the catalyst-free method of nanowire growth. As reported previously, the 5-fold twinned Cu nanowire in a Cu crystallization system is the most common nanostructure with high aspect ratios, but internal stresses appear in unstable structures with an angle deviating from the ideal 70.5° between twin boundaries. − …”

Diffusion controlling porphyrin assembled structures

“…In such a condition, a molecular concentration gradient is easily formed around the growth fronts of a nucleus as a result of quick consumption and slow delivery of molecules. If a nucleus grows in a concentration gradient, the anisotropic growth is easily triggered, in which the growth of the long axis is in favor, because it is close to high concentration of chemicals [24][25][26]. Hence the plate-like nuclei grow along the long axes, forming thin stripe-like structures at the low volume ratio of ethanol.…”

Study of irradiation effect of Xe+22and Kr+14ions on structural properties of Zn nanotubes

“…Among a vast variety of metal nanomaterials, nanostructures based on Zn [11] and ZnO oxide [12] occupy a special posi tion. They possess both semiconductor and piezoelectric properties [13][14][15], which can serve as the basis for electro mechanically coupled sensors and converters. They are also relatively biologically safe, have low toxicity and biocompat ibility [16][17][18][19][20].…”

“…Also, a crucial factor for the practical application of nano structures is the study of the effect of ionizing radiation on struc tural and conductive properties of nanomaterials. Moreover, the assessment of the possibility of using ionizing radiation for directional modification of physicalchemical and structural properties of nanostructures is also essential [1,11,13,21,22]. When nanostructured materials are irradiated with heavy ion beams, additional defects appear in the crystal structure.…”