In Situ Investigation of Defect-Free Copper Nanowire Growth

Abstract

The fabrication and placement of high purity nanometals, such as one-dimensional copper (Cu) nanowires, for interconnection in integrated devices have been among the most important technological developments in recent years. Structural stability and oxidation prevention have been the key issues, and the defect control in Cu nanowire growth has been found to be important. Here, we report the synthesis of defect-free single-crystalline Cu nanowires by controlling the surface-assisted heterogeneous nucleation of Cu atomic layering on the graphite-like loop of an amorphous carbon (a-C) lacey film surface. Without a metal-catalyst or induced defects, the high quality Cu nanowires formed with high aspect ratio and high growth rate of 578 nm/s. The dynamic study of the growth of heterogeneous nanowires was conducted in situ with a high-resolution transmission electron microscope. The study illuminates the new mechanism by heterogeneous nucleation control and laying the groundwork for better understanding of heterosurface-assisted nucleation of defect-free Cu nanowire on a-C lacey film.

Electron Beam Irradiation-Induced Deoxidation and Atomic Flattening on the Copper Surface

“…The Cu nanowires were fabricated by ultrahigh vacuum annealing in a JEOL 2000V UHV-TEM without metal catalyst on the Cu grid with an amorphous carbon substrate. The high-purity Cu nanowire provides a high aspect ratio and hexagonal column morphology with symmetry (111) and (002) plane, which has been reported previously …”

“…Figure f shows the hexagonal column Cu nanowire morphology and the schematic illustration of the e-beam irradiation experiment. More details of hexagonal column Cu nanowires have been reported in the previous study . Following the experimental design, the deoxidation of Cu 2 O on the Cu(111) surface was reported by HRTEM observations in the following steps as shown in Figure a–c (associated atomic models are shown in Figure d–f).…”

“…The high-purity Cu nanowire provides a high aspect ratio and hexagonal column morphology with symmetry (111) and (002) plane, which has been reported previously. 33 In Situ e-Beam Irradiation. The in situ e-beam irradiation experiment was carried out in a JEOL JEM-ARM200F TEM operated at 200 kV.…”

Synthesis, Characterization, and In Situ Antifungal and Cytotoxicity Evaluation of Ascorbic Acid-Capped Copper Nanoparticles

“…During the synthesis of the CuNPs, a color change from a dark-brown solution (formed after the immediate contact with ascorbic acid) to a reddish-brown after the reflux was visualized, indicating the formation of stable CuNPs [12,32]. Thus, we applied UV-Vis analysis and detected that the SPR band of our NPs was at 530 nm (Figure 2, see inset), due to a possible transition movement of the valence electron of Cu.…”

“…Moreover, when bulk Cu is transformed to CuNPs, the physicochemical and biological properties of Cu can be improved (e.g., the catalytic, optical, electrical, and more importantly the antimicrobial capability) [9]. Several strategies have been explored in order to synthesize CuNPs, for example, laser ablation, thermal modifications, vacuum vapor deposition, and chemical reduction [10][11][12]. Interestingly, chemical reduction offers a versatile and easy way to synthesize reproducible, stable, and controllable CuNPs, by the reduction and stabilization of Cu +2 ions to Cu 0 by capping with organic compounds (if the synthesis is carried out under reflux conditions) [13,14].…”