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In this letter we demonstrate a simple carbon nanotube patterning technique that combines nanotube film bonding, photolithography, and O2 plasma etching. Well defined carbon nanotube film structures with line widths less than ∼1.5 μm and thickness ranging from 40 to 780 nm were readily fabricated. A micro-optomechanical actuator based on this process has been demonstrated. This patterning process can be utilized for the integration of nanomaterials for wide variety of devices including microeletromechanical systems, field emission displays, and micro-optomechanical systems (MOMS). [ABSTRACT FROM AUTHOR]

For organic thin-film transistors where source-drain contacts are defined on the gate dielectric prior to the deposition of the semiconductor (“bottom-contact” configuration), the gate dielectric is often treated with a self-assembled molecular monolayer prior to deposition of the organic semiconductor. In this letter, we describe a method to apply an ultrathin solution-processed polymer layer as surface treatment. Our method is compatible with the use of the bottom-contact configuration, despite the fact that the polymeric surface treatment does not stand a photolithographic step. Furthermore, we show that our surface treatment results in superior transistor performance. [ABSTRACT FROM AUTHOR]

An application is demonstrated for the much maligned standing wave in photolithography that is responsible for the sidewall corrugations in photoresist patterns. We demonstrate the realization of a polydimethylsiloxane (PDMS) scattering mask through the casting of these sidewall corrugations and their application as the masking components in an otherwise transparent bulk of PDMS. Photoresist structures with widths in the order of 80 nm are realized by the application of this mask, demonstrating excellent correlation with the lateral depths of the sidewall corrugations. The continuity of the sidewall corrugations around corners makes both straight and curved lines realizable with equal simplicity. [ABSTRACT FROM AUTHOR]

A transfer fabrication technique is developed to construct embedded and inverted micro/nanostructures that cannot be readily built by other methods. Transfer patterning/printing is used for the fabrication, which involves transferring a patterned layer on a flat substrate to another substrate that has a higher work of adhesion with the layer than the flat substrate. The technique is relatively simple and fast (∼10 s). Inversion of a shape that is made possible by the transfer is the basic concept. This inversion allows fabrication of three-dimensional embedded structures through multiple stacking. The technique could open new avenues for various applications. [ABSTRACT FROM AUTHOR]

A new method of fabricating porous silicon emitting in the ultraviolet (UV) spectral region is presented. This method uses photoetching in an aqueous salt (KF) solution. Strong UV photoluminescence is observed at ∼3.3 eV with a full width at a half maximum of ∼0.1 eV, which is much narrower than those reported previously. Fourier transform infrared spectroscopy suggests that the surface oxide produced during photoetching plays an important role in the UV emission of the KF-prepared PSi. [ABSTRACT FROM AUTHOR]

We report on a high-speed flexible display based on a deformed helix ferroelectric liquid crystal (DHFLC) in a vertically aligned configuration. The mechanical stability of the flexible DHFLC display was achieved using a periodic array of columnar spacers formed directly on the top side of in-plane electrodes by the photolithography technique. Several unique features of display performances such as flexibility, uniform alignment, fast response, and gray scale capability were obtained. The switching time was found to be a few hundred microseconds. [ABSTRACT FROM AUTHOR]

This paper describes a technique for fabricating three-dimensional, metallic, pyramidal microstructures with base dimensions of 1-2 μm, wall thicknesses of ~100-200 nm, and tip-curvature radius of ~50 nm. The procedure begins with the fabrication of pyramidal pits in the surface of an n-doped silicon substrate. An electrically insulating surface layer of SiO2 covers the regions outside the pits. These pits are patterned using either conventional photolithography or soft lithography and formed by selective anisotropic etching. The resulting topographically patterned silicon serves as the cathode for the selective electrodeposition of metal in the pyramidal pits. Removing the silicon template by etching generates free-standing, pyramidal, metallic microstructures. [ABSTRACT FROM AUTHOR]

Photothermal bending of strips of polyvinylidene fluoride was initiated by a laser beam with a power of a few milliwatts. A bending strip generated a force of 10-4 N that propelled a 1 g oscillating wheel of a mechanical clock. The frequency of photomechanical resonance at pulsed illumination was inversely proportional to the length of the strip. The proposed model explained bending as a result of uneven thermal expansion on opposite sides of the strip. The model predicted, in agreement with experiment, that the force is proportional to beam power and does not depend on the shape or position of the beam in the strip. [ABSTRACT FROM AUTHOR]

We have used deposited polymer nanofibers as templates for the formation of functional nanomechanical devices, interfaced to lithographically defined surface microstructures. The deposition of oriented poly(methyl methacrylate) nanofibers, combined with contact photolithography, created silicon nitride nanomechanical oscillators with dimensions on the order of 100 nm. We used contact photolithography to define the support structures for the oscillators. The moving beams were defined in the device layer by using the deposited fiber as a mask for reactive ion etching using a CF4 plasma chemistry, followed by removal of a sacrificial underlying layer. After releasing the devices, the frequencies of the modes of oscillation of the beams were determined by laser interference techniques. The devices would self-oscillate due to the interferometric effects of the continuous wave (CW) detection laser. The oriented polymeric nanofiber deposition method, used in this experiment, offers an approach for the rapid formation of arrays of nanomechanical devices, connected to micromechanical structures, that would be difficult to form using a completely self-assembled or completely lithographic approach. This direction may provide a useful method for realizing nanoscale device architectures in a variety of active materials. [ABSTRACT FROM AUTHOR]

Glassy, polydomain azobenzene liquid crystal polymer networks (azo-LCNs) have been synthesized, characterized, and modeled to understand composition dependence on large amplitude, bidirectional bending, and twisting deformation upon irradiation with linearly polarized blue-green (440-514 nm) light. These materials exhibit interesting properties for adaptive structure applications in which the shape of the photoresponsive material can be rapidly reconfigured with light. The basis for the photomechanical output observed in these materials is absorption of actinic light by azobenzene, which upon photoisomerization dictates an internal stress within the local polymer network. The photoinduced evolution of the underlying liquid crystal microstructure is manifested as macroscopic deformation of the glassy polymer film. Accordingly, this work examines the polarization-controlled bidirectional bending of highly concentrated azo-LCN materials and correlates the macroscopic output (observed as bending) to measured blocked stresses upon irradiation with blue-green light of varying polarization. The resulting photomechanical output is highly dependent on the concentration of crosslinked azobenzene mesogens employed in the formulation. Experiments that quantify photomechanical bending and photogenerated stress are compared to a large deformation photomechanical shell model to quantify the effect of polarized light interactions with the material during static and dynamic polarized light induced deformation. The model comparisons illustrate differences in internal photostrain and deformation rates as a function of composition and external mechanical constraints. [ABSTRACT FROM AUTHOR]

The influence of a shallow-level donor impurity on the temperature dependence of microhardness and the photomechanical effect in single-crystal Si is investigated. It is demonstrated that, as the impurity concentration increases, the temperature dependence of the microhardness measured in the dark changes. The magnitude of the photomechanical effect and the temperature range of its existence decrease. The data obtained are explained on the basis of the mechanism of decreasing the microhardness with increasing the temperature due to increasing the density of phonons and antibonding quasiparticles. In this case, the concentration redistribution of antibonding quasiparticles that are induced by band-to-band transitions and transitions from impurity levels, which exert a different antibonding action, is responsible for the variations observed in the photomechanical effect. [ABSTRACT FROM AUTHOR]

An X-band, end-coupled ring resonator has been fabricated photolithographically by depositing Cr–Cu–Au film on an LiZnTi polycrystalline ferrite substrate. Resonator characteristics have been studied by keeping it in the magnetic field, which was varied from 0 to 3.0 kG. Broadband tunability of 3.1 GHz was achieved with a minimum insertion loss of -11.17 dB when the direction of the magnetic field was changed from transverse to longitudinal to the wave propagation in coupling lines. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 161–163, 2001. [ABSTRACT FROM AUTHOR]

The elements of the position sensitive semiconductor detectors are separated by grooves that must have high resistance and must be also time stable, independently of the environment where the detector is placed. Therefore, one theme of study inherent to the fabrication of position sensitive detectors is the investigation of passivation techniques, which make possible to reduce the environment influence on the detectors properties. Si (Li), Si (HP) and Ge (HP) guard-ring structural detectors have been developed by two different methods, ion implantation combined with photolithography and plasma etching, and metal evaporation with the use of a mask. The application of new passivation techniques on these detectors led to successive reduction of their reverse currents, which made possible to get the desired final stable characteristics. [ABSTRACT FROM AUTHOR]

Presents letters to the editor about pathological science and photomechanical and electromechanical effects in response to Robert N. Hall's epilogue "Pathological Science" in the October 1989 issue on page 36.

The article highlights the career of daguerreotypist Henry E. Insley. He was a known character in the history of photography in the U.S. Insley was best known for his invention of the illuminated daguerreotype, a vignette process patented on January 6, 1852. Some of his accomplishments included the use of double mirrors to reflect sunlight into his studio. He was also credited for taking the first instantaneous picture of a man walking in the street. Other references to a daguerreotypist named Insley appeared in the late 1840's. However, the relationship to Insley, if any, was unclear.

Front Cover: Photomechanical polymeric materials could be the future for building light‐driven soft robotic actuators. In article number 1800815, Robert F. Shepherd and co‐workers propose a simple synthesis and processing route for the fabrication of a self‐healing photomechanical elastomer. This material enables the construction of complex 3D shapes using a simple 'cut and paste' assembly. [ABSTRACT FROM AUTHOR]

In this work, we demonstrate the importance of laser pulse overlap in controlling the ablation process of a thin film just above the single pulse material ablation threshold. A 532 nm, 15 ps ultrafast diode pump solid-state (DPSS) laser has been employed to pattern a gold alloy source-drain layer during the production of organic thin film transistor (OTFT) for flexible display applications. Maintaining the laser fluence constantly above and in proximity of the ablation threshold value, different process windows are identified by varying the pulse overlap. With less than four overlapping pulses per area, a debris-free removal process is achieved with almost no edge delamination. By increasing the number of pulses per area up to 20, edge delamination progressively grows stronger and eventually ablation terminates altogether. If the pulse overlap increases further, ablation starts again but with more evidence for thermal, cumulative irradiation effects. This behavior can be attributed to the progressive transition from initially a photomechanical stress-assisted ablation process, dominant at low pulse overlap to increasingly a more thermally driven removal process, at higher pulse overlaps. [ABSTRACT FROM AUTHOR]

Amorphous InGaZnO4neuron transistors based on multi-gate electric-double-layer modulation are fabricated by photolithography processes. The sweeping rate dependent output current and hysteresis loop are observed due to the proton dynamic process in the SiO2nanogranular electrolyte. Temporal summation such as paired-pulse facilitation is mimicked in the neuron transistor with one presynaptic input. At the same time, supralinear spatial summation of two presynaptic inputs is also successfully mimicked in the neuron transistor with two presynaptic inputs. Our InGaZnO4neuron transistors with temporal and spatial summation function are interesting for the brain-inspired neuromorphic system. [ABSTRACT FROM AUTHOR]

A surfactant-assisted seeded-growth method is used to form single-crystal platelets composed of 9-methylanthracene with two different internal molecular orientations. The more stable form exhibits a photoinduced twisting, as observed previously for 9-methylanthracene microribbons grown by the floating drop method. However, the newly discovered elongated hexagonal platelets undergo a photoinduced rolling-up and unrolling. The ability of the rolled-up cylindrical shape to trap superparamagnetic nanoparticles enables it to be carried along in a magnetic field gradient. The new photoinduced shape change, made possible by a novel surfactant-assisted crystal growth method, opens up the possibility of using light to modulate the crystal translational motion., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The article discusses the growth of photolithography techniques which is used for fabrication to the small parts of devices. It mentions that the scientist should use molecules that can self-assemble into nanostructures by phase separation application such as in the coercion of 48 nanometer film of PS-PEO diblock copolymer. It also emphasizes that its certainly possible to miniaturize the polymer microdomains.

A calendar of experimental mechanics-related congresses for 2010-2011 is presented which includes the "Institution of Mechanical Engineers Seminar on Engineering Structures Survival: Blast and Impact Protection," at Nottingham, Great Britain on October 7, 2010, "Photomechanics 2011," at Brussels, Belgium on February 7-9, 2011, and the "International Conference on Manufacturing of Advanced Composites (ICMAC 2011)" at Belfast, Northern Ireland on March 22-24, 2011.

The authors propose and demonstrate how to use an ordinary optical microscope as a flexible optical lithography tool. Until the advent of digital cameras, most high power optical microscopes had a vertical cone shaped fixture with a Polaroid film holder to record optical micrographs on the film. For conversion to lithography, the Polaroid film holder is simply removed and a vu-graph transparency, which serves as a mask, is substituted in the plane of the film. The transparency has the desired pattern printed on it by a laser printer or a copier. Ideally, the transparency has to be backlighted by a converging light source such that (ignoring diffraction) a pinhole anywhere in the transparency illuminates the entire lens at the base of the cone shaped fixture. The authors used a 11.4 cm diameter, 12.7 cm focal length Fresnel lens and a fiber light to generate the appropriately converging mask illumination. With the highest magnification, 100× lens the image on the mask was demagnified approximately by 700× on the sample. With this lens, the authors could expose lines of slightly less than 1 μm width. [ABSTRACT FROM AUTHOR]

The article reports that methods for in situ light-directed synthesis have enabled the production of linear polymers in spatial arrays, including peptides, oligocarbamates, oligonucleotides, and peptoids. The polymers are assembled through iterative unmasking of reactive groups and monomer coupling cycles. The locations of products in the array are controlled by photolithography using physical masks, or more flexibly, by light reflected from a digital micromirror device to produce arrays with up to 786 432 features. The creation of small molecule microarrays, by in situ synthesis or through the robotic spotting of compound libraries, allows binding assays to be conducted simultaneously on all members of the small molecule array, greatly reducing the time and cost of high throughput screens.

Micro-engineering expert Marc Madou of the University of California, Irvine, and his colleagues are targeting their efforts at micro-batteries, small power cells used to juice devices such as pacemakers, hearing aids, smart cards, and remote sensors. Like all batteries, micro-batteries work by shuttling electron-toting compounds from a negatively charged electrode to one that is positively charged, where the electrons are siphoned off. Madou and colleagues have developed a computer-chip-patterning technology known as photolithography. They shined ultraviolet light through a stencil pocked with an array of holes. The light hit an underlying organic film called a photoresist and caused the material to polymerize.

Describes the photomechanical actuation and manipulation of the electronic properties of linear pi-conjugated systems. Covalent fixation of a photostimulable group on two fixed points of an oligothiopene chain; Production on conformotional changes and reversible modifications of the electronic properties of the pi-conjugated system.