Nanoscale Technique Research Articles

Dithiolene vanadium complexes based regulated domain arrangement by colloidal lithography

We have successfully fabricated nanometer-sized ring structures of paramagnetic metal complex of ( n-Bu 4N) 2[(dcbdt) 2VO], (dcbdt = 4,5-dicyanobenzene-1,2-dithiolato) on glass substrates using a colloidal lithography technique. Trimethylammonium substituted polystyrene particles of a 200 nm diameter as a template of deposits were adsorbed on a surface of glass substrate by electrostatic interactions between particles and substrate. The coverage of the particles monolayer obtained by immersion of a substrate in a 0.1 wt% particle solution was 0.30. After casting the metal complex solution on the particle monolayer and removing the particles by an adhesive tape, we obtained nano-scale rings of around 130 nm outer diameter and around 10 nm height on a surface of the substrate reflecting the position of particle templates. The nano-scale ring structure discovered in our study seems highly practical due to its simple and easy fabrication method. We believe this structure has the potential to serve as a low cost nano-scale lithography technique as well as scientific research.

Mammalian cell nano structures visualized by cryo Hilbert differential contrast transmission electron microscopy

We applied the Hilbert differential contrast phase electron microscopy technique for the first time to mammalian cells, Ptk2 cells. Intracellular architectures such as the cytoskeletal network, membranous organelles, and mitochondria were observed without prior removal of cell membranes or extraction of soluble proteins. The attachment of mitochondria and membrane organelles with microtubules were observed. Microtubules were depolymerized by nocodazole treatment as expected. Thus, Hilbert differential contrast phase electron microscopy of vitrified cells is a nano-scale molecular imaging technique that opens up new vistas for exploring the supramolecular organization of the mammalian cell.

A nano-scale alignment method for imprint lithography

A novel nano-scale alignment technique based on moire signal for room-temperature imprint lithography in the submicron realm is proposed. The moire signals generated by two pairs of quadruple gratings on mold and wafer are optically projected onto two photo-detector arrays, then the detected moire signals are used to estimate the alignment errors in the x and y directions. The experiment results indicate that complex differential moire signal is sensitive to relative displacement of the mold and wafer, and the alignment accuracy obtained in the x and y directions and in ϑ are ±20 nm, ±25 nm and ±1 μrad (3σ), respectively. They can meet the requirements of alignment accuracy for submicron imprint lithography.

Development of a nanoscale fatigue measurement technique and its application to ultrathin amorphous carbon coatings

A technique to study nanofatigue behavior of coatings has been developed. Based on measurements of amorphous carbon coatings (DLC), higher hardness, fracture toughness and adhesion strength are responsible for a longer fatigue life. This technique can be satisfactorily used to simulate and study damage in head-disk and MEMS/NEMS interfaces.

Nanoscale Technique Prints Metal Films with Reusable Stamps and Tailored Surface Chemistry

Nanoscale Technique Prints Metal Films with Reusable Stamps and Tailored Surface Chemistry

Generation of electrospun fibers of nylon 6 and nylon 6-montmorillonite nanocomposite

Dissolution and reprocessing of exfoliated montmorillonite–nylon 6 (NLS) nanocomposite is demonstrated, illustrating the potential of using polymer nanocomposites as the foundation for fabricating nano- and mesoscopic structures, nanofibers in this case, and thus exerting hierarchical control of morphology and form through the combination of a nanostructured material and a nanoscale fabrication technique. Exfoliated morphology, present in the melt-fabricated NLS nanocomposite, was preserved in cast films and electrospun fibers from hexafluoroisopropanol solution. However, addition of a few percent N, N-dimethyl formamide resulted in agglomeration of the dispersed montmorillonite layers and an overall mixed morphology, demonstrating solvent partitioning and the delicate enthalpic balance necessary to maintain layer dispersion. Fibers and nanofibers of NLS nanocomposite (diameters between 100 and 500 nm) were electrospun from solution, and collected as non-woven fabrics, or as aligned yarns. Together with these cylindrical shaped fibers and nanofibers, ribbon shaped fibers ( width∼10 μm, thickness∼100–200 nm ) were also found in the products. The electrospinning process resulted in highly aligned montmorillonite layers (layer normal perpendicular to the fiber axis) and nylon 6 crystallites (layer normal parallel to fiber axis).

Quantitative metrology study of Cu/SiO2 interconnect structures using fluorescence x-ray microscopy

We demonstrate the capability of fluorescence x-ray microscopy with a 0.25 μm beam for in situ measurements of Cu-wiring interconnects of submicron dimensions. We are able to measure submicron line widths, lengths, and thicknesses of both Cu and W structures, and a Ta liner in the test vehicle, to the absolute accuracy of 0.03 μm, and a relative accuracy of ∼4% in lateral dimensions, and ∼10% in heights. The shape of a buried electromigration void was also determined. This nanoscale nondestructive characterization technique promises to be powerful for a variety of materials systems.

Writing and Reading at Nanoscale with a Scanning Tunneling Microscope

The scanning tunneling microscope (STM) has grown and evolved at an incredible rate. Now STM not only is used as a powerful imaging tool to provide atomic resolution surface topography but also quickly becomes a nanoscale manipulator after slight modification. In this paper, we describe a nanoscale lithography technique, which was developed by combining STM with an electrochemical cell. We have demonstrated the feasibility of this technique, which allows us to write, read, and erase letters at a nanoscale level. At present, there still exist some difficulties but we believe that the ability to write, edit, and archive symbols and patterns on a nanoscale level constitutes a significant advance and an enabling concept in nanolithography

Density measurement and disorder of lead selenide

Retention of plasma-implanted D is studied in W targets damaged by a Cu ion beam at up to 0.2 dpa with sample temperatures between 300 K and 1200 K. At a D plasma ion fluence of 1024/m2 on samples damaged to 0.2 dpa at 300 K, the retained D retention inventory is 4.6 × 1020 D/m2, about ∼5.5 times higher than in undamaged samples. The retained inventory drops to 9 × 1019 D/m2 for samples damaged to 0.2 dpa at 1000 K, consistent with onset of vacancy annealing at a rate sufficient to overcome the elevated rate of ion beam damage; at a damage temperature of 1200 K retention is nearly equal to values seen in undamaged materials. A nano-scale technique provides thermal conductivity measurements from the Cu-ion beam displacement damaged region. We find the thermal conductivity of W damaged to 0.2 dpa at room temperature drops from the un-irradiated value of 182 ± 3.3 W/m K to 53 ± 8 W/m K.