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We developed a localized plasma-enhanced chemical vapor deposition (PE-CVD) technique to deposit silicon oxide with a sub-micrometer width on a substrate using an atmospheric pressure plasma jet (APPJ) irradiated from a nanopipette nozzle. To realize fine material deposition, hexamethyldisiloxane (HMDSO) vapor was blown into the localized helium APPJ irradiated from the sub-micrometer aperture of the nanpopipette with the jet length limited to the aperture size of the nanopipette. The irradiation distance was controlled using a shear-force positioning technique using scanning probe microscopy (SPM). The proposed system successfully deposited silicon oxide dots with sub-micrometer width on a substrate. After the deposition, the topography of the deposited surface was observed by scanning the nanopipette, which can be used as an SPM probe. The localized PE-CVD properties were systematically investigated by varying the deposition parameters. The amount of deposited material could be controlled by the flow rate of the carrier gas of the HMDSO vapor, APPJ irradiation time, and nanopipette–substrate surface irradiation distance.

A fast integrated mobility spectrometer (FIMS) was previously developed to characterize submicron aerosol size distributions at a frequency of 1 Hz and with high size resolution and counting statistics ( Kulkarni & Wang (2006a) , Kulkarni & Wang (2006b) ; Olfert, Kulkarni, & Wang, 2008 ). However, the dynamic size range of the FIMS was limited to one decade in particle electrical mobility. It was proposed that the FIMS dynamic size range can be greatly increased by using a spatially varying electric field ( Wang, 2009 ). This electric field creates regions with drastically different field strengths in the separator, such that particles of a wide diameter range can be simultaneously classified and subsequently measured. A FIMS incorporating this spatially varying electric field is developed. This paper describes the theoretical frame work and numerical simulations of the FIMS with extended dynamic size range, including the spatially varying electric field, particle trajectories, activation of separated particles in the condenser, and the transfer function, transmission efficiency, and mobility resolution. The influences of the particle Brownian motion on FIMS transfer function and mobility resolution are examined. The simulation results indicate that the FIMS incorporating the spatially varying electric field is capable of measuring aerosol size distribution from 8 to 600 nm with high time resolution. The experimental characterization of the FIMS is presented in an accompanying paper.

The growth mechanism of exceptionally long N-polar GaN sub-micrometer (sub-μm) rods has not been revealed to date. In this work, we investigated the effects of the V/III molar ratio and HCl (diluted in carrier gas) on the lengthening of a MOCVD-GaN rod template by HVPE. It is found that a low V/III molar ratio and HCl (diluted in carrier gas) help form vertical sidewalls and suppress the lateral growth on the top part of exceptionally long GaN sub-μm rods. Simulation results revealed that the low V/III molar ratio leads to reactive species distributing almost exclusively on the top part of GaN rods, which can effectively prevent crystal growth on the bottom of GaN rods. Chlorine ions support the growth by etching the sidewalls. After growth, the diameter and length of each GaN rod are more than 1.5 μm and 70–80 μm, respectively. Finally, an empirical growth model was developed to account for the exceptionally long GaN sub-μm rods under HVPE growth.

Determining the structural chirality of biomolecules is of vital importance in bioscience and biomedicine. Conventional methods for characterizing molecular chirality, e.g., circular dichroism (CD) spectroscopy, require high-concentration specimens due to the weak electronic CD signals of biomolecules such as amino acids. Artificially designed chiral plasmonic metastructures exhibit strong intrinsic chirality. However, the significant size mismatch between metastructures and biomolecules makes the former unsuitable for chirality-recognition-based molecular discrimination. Fortunately, constructing metallic architectures through molecular self-assembly allows chirality transfer from sub-nanometer biomolecules to sub-micrometer, intrinsically achiral plasmonic metastructures by means of either near-field interaction or chirality inheritance, resulting in hybrid systems with CD signals orders of magnitude larger than that of pristine biomolecules. This exotic property provides a new means to determine molecular chirality at extremely low concentrations (ideally at the single-molecule level). Herein, three strategies of chirality transfer from sub-nanometer biomolecules to sub-micrometer metallic metastructures are analyzed. The physiochemical mechanisms responsible for chirality transfer are elaborated and new fascinating opportunities for employing plasmonic metastructures in chirality-based biosensing and bioimaging are outlined.

In this work, photoanodes with sub-micrometer cavities of different sizes and ratios were easily fabricated by burning off the polystyrene sub-micrometer spheres (PSSs) embedded in TiO 2 paste. When the original PSS in the anode was 500 nm in diameter and the ratio was 100 μl (5 vol%) PSSs solution mixed with 0.1 g TiO 2 nanoparticles, the optimized performance of the fabricated dye-sensitized solar cells (DSSCs) was remarkably ∼48% higher than that of pristine TiO 2 DSSCs without sub-micrometer cavities in control group. This great performance improvement was attributed to the ability of enhancing light scattering and maintaining low resistance with the introduction of optimized amount of sub-micrometer cavities. This general strategy should help to design and develop the future DSSCs with better performance.

High-resolution three-dimensional (3-D) imaging of heterogeneous metals was performed by high-energy magnified synchrotron tomography using Kirkpatrick–Baez focusing optics, achieving voxel sizes of (50–60 nm)3. Holotomographic reconstructions were created based on absorption and phase contrast. Microstructural features as small as ∼180 nm were detected in ternary eutectic Al–Mg2Si–Si, SiC-particle-reinforced AlCu4, near-β Ti–10V–2Fe–3Al, and in TiB-reinforced α + β Ti–6Al–4V. The phase-retrieval procedure yielded enough contrast to segment the individual phases and analyze their shapes and 3-D architecture.

Sub-micrometer-sized tungsten-whisker arrays are synthesized by a catalyst- and template-free vapor-deposition process. The resultant whiskers have a hexagonal cross-section, sharp pyramidal tip, and large aspect ratio. The excellent field-emission properties of the whisker arrays, which can be tuned varying the diameters of the synthesized whiskers, are demonstrated.

Macroscopic to sub-micrometer-scale patterns and objects are generated by successive miniaturization of an original pattern using the volume-shrinking characteristics of hydrogels. A pattern from a stamp is transferred onto a hydrogel block, which is then dried to shrink its size. The shrunk pattern is subsequently transferred to a polymer stamp, which can be used as master for the next cycle. The figure shows the shrinking of the patterns of a CD (left) and a DVD (right).

This work was supported financially by the Korea Science and Engineering Foundation (KOSEF) under the National Creative Research Initiative Project of the Ministry of Science and Technology (MOST), Korea and partially by LG Siltron Co.

Periodic arrays of micrometer and sub-micrometer magnetic structures prepared by nanoindentation of a nonmagnetic intermetallic compound

In-situ heating in a transmission electron microscope was used to investigate the stress-relief mechanisms occurring in the 3–4 nm thick aluminum-oxide films present on the surfaces of submicron Al–11.6% Si powder particles during melting. Experimental observations show that the aluminum-oxide shell undergoes creep to relieve the high stress generated by the expanding liquid during melting. Surface oxides that contain defects do not undergo uniform creep and are prone to cracking, which causes ejection of some of the pressurized liquid inside the particles through the crack. Calculations were performed to estimate the stresses generated on the aluminum-oxide shell by the expanding liquid and the possible effect of the stress generated by the confining oxide shell on the melting temperature of the Al–Si alloy. The calculations show that the oxide film creeps to avoid the high tangential stress (on the order of 15 GPa) produced by the expanding liquid and that this creep mechanism prevents the oxide from markedly changing the melting behavior of the Al–Si particles.

A new optical measurement method for evaluating the defects on a silicon wafer surface quantitatively, which will be able to be applied to in-process measurement, is presented. The experimental system for measuring the defects consists of the Fourier transform optical system using of a high-power objective. In order to verify the feasibility of application of this method to in-process measurement, scanning experiments for small particles, which are typical defects on the silicon wafer surface, are carried out. It is shown that the proposed method is effective for detecting and discriminating the small defects with the size of sub micrometer order.

Sub-micrometer length copper fibers are obtained via polymer supported electrospinning and subsequent thermal treatment. The copper nature of the fibers is confirmed by using energy- dispersive X-ray analysis and wide- angle X-ray analysis (see figure). The copper fibers show metallic conductivity as confirmed by conductance measurements in a low-energy electron point source microscope.

Main idea for every dimensional measurement is the detection of the surfaces or a group of points on an object by means of a probing system. The application of this fundamental idea in the field of micro and nano metrology, with size aspects or part tolerances in the sub micrometer regions, is very challenging. This task requires the application of precise length measuring systems for setting up a coordinate system and suitable sensors. The aim of this paper is to demonstrate recent scientific and technological developments by means of the most promising existing applications in this field.

Optical micro parts, such as glass fibres, require handling and alignment accuracies down to the sub micrometer range. Addressing this task, one aim of the Fraunhofer IPT is the development of new concepts of active gripper systems. In this context a highly integrated, adaptive, rugged and economical gripper system particularly for accurate handling and alignment of flexible micro parts down to the sub-micron level has been developed. This gripper system can be used on conventional robot systems for carrying out micro-assembly operations. The robot system does the pre-positioning, the tolerances necessary for the micro-assembly are subsequently realized directly at the tip of the gripper with the gripper integrated multi-axes system. Positioning systems that achieve the required positioning increments in the sub micron range are already existent. However, the problem of such systems is that they are normally highly sensitive against mechanical impact and extremely cost intensive. In this paper the development of a highly robust gripper-integrable axes system and its integration in a novel gripper design with a multi-axis adjustment system is presented.

Single cell electrophysiological analyses were demonstrated via sub-micrometer openings using micro-and nano-machining technologies. In the prototype demonstration, a 6GΩ seal resistance was achieved on a HeLa cell, a cervical cancer cell line with size between 10~20μm, using the microfabricated electrophysiological system with opening size of 500nm in diameter and the measured electrolyte pipette resistance is 200kΩ. In a second experiment on a vacuolar yeast cell of 3~5μm in size, using a device with 800nm opening, a 500MΩ seal resistance was achieved and the measured electrolyte pipette resistance is 1MΩ.