Silicon nanostructures have attracted enormous attention in the past two decades due to their unique optical properties that cannot be observed in their bulk counterparts. However, since intrinsic silicon has negligible response to infrared photons (λ>1.15 μm) with energies lower than its bandgap energy, it poses a great challenge to use silicon as an active absorbing material for infrared photodetection. In order to realize all-silicon CMOS compatible infrared photodetectors, various approaches have been investigated including incorporation of germanium with silicon as the optically responsive element, two photon absorption process, and surface-plasmon Schottky detectors. The success of these earlier approaches has been limited. (more...)

This invention is a new process to create microlens arrays and microwells in plastic.Microlenses are primarily fabricated from glass and optical grade polymers. One such plastic is polystyrene (PS), which has a high index of refraction, high optical transmission, and spectral band pass. Glass microlens array production is comparatively older but polymers have been favored for their affordability and ease of manufacture as well as the ability to control their thermal and mechanical properties. Previous methods for polymer arrays include: photoresist reflow, microjet printing, and direct laser writing. High temperature reflow of photoresist to create such rounded high aspect ratio structures is difficult and often results in rather shallow lenses. Then, to transfer the patterns into hard plastics via hot embossing, costly and slow electroplating is required. Instead, we created our molds using a laser jet printer and a technique which solves the shortcomings of modern manufacturing techniques. We address the issue of microfabricating high aspect ratio structures with high curvature (deep and round). Reflow of photoresist, the common way to make such structures typically results in shallow radii of curvature structures. Moreover, to transfer such structures to hard plastics typically require hot embossing, which requires a metallized (e.g. nickel electroplated) mold. This is very slow and expensive. Our technique allows our masters to be created with a laserjet printer. Then we can do soft lithography to transfer this to PDMS. Finally, we use the PDMS mold for the hot embossing back into a thermoplastic sheet. One problem solved by plastic microwells is the culturing of embryoid bodies (EB). EBs require size, morphology, uniformity and reproducibility control. Previous methods often required a trade-off between quantity and uniformity. PDMS microwells were a great improvement and did much to address these concerns. PDMS have the drawbacks of non-selective absorption, swelling, and poor mechanicalproperties. Polymer microlens arrays have been seen to have much potential but popular techniques for fabrication have various problems. For example,photoresist reflow suffers from chemical and thermal instability, has high requirements for consistency and reproducibility, and need photosensitive material. Some such disadvantages have been overcome but very often require expensive equipment and a time consuming process. This is new method of creating features on the microscale. The inverse of features previously formed in polydimethylsiloxane (PDMS) is transferred to a thermoplastic such as prestressed polystyrene. This is performed by placing the thermoplastic on the PDMS mold, forcing the substrates towards one another through uniform pressure, and baking them past the glass transition temperature of the thermoplastic. Inherent in this process are the multitude of techniques to pattern in PDMS and the ability of thermoplastics to become malleable when properly heated. The purpose of this is to create microstructures that may be used in various applications such as embryoid body culture or optical communication and interconnection. To demonstrate ability of the microlens arrays, we conducted a simple laser experiment was performed. As the laser was shown through the 460 um microlens array a z-stack of images were acquired. Using this information the numerical aperture for several lens were calculated to approximately 0.14. With this demonstration the functionality of this new microlens array design has been proven. This new, inexpensive and relatively simple method to fabricate microlens arrays in a hard plastic with excellent optical properties can provide a platform for optical applications. (more...)

This invention relates to methodologies and techniques which utilize programmable functionalized self-assembling nucleic acids, nucleic acid modified structures, and other selective affinity or binding moieties as building blocks for: creating molecular electronic and photonic mechanisms; for the organization, assembly, and interconnection of nanostructures, submicron and micron sized components onto silicon or other materials; for the organization, assembly, and interconnection of nanostructures, submicron and micron sized components within perimeters of microelectronic or optoelectronic components and devices; for creating, arraying, and manufacturing photonic and electronic structures, devices, and systems; for the development of a high bit density three and four dimensional optical data storage materials and devices; and for development of low density optical memory for applications in authentication, anti-counterfeiting, and encryption of information in document or goods. (more...)

High-throughput, automated, large-scale mircoarry format assay in a short time frame and at low cost. (more...)

Superhydrophobic surfaces have attracted tremendous attention due to their self-cleaning, anti-contamination, and anti-sticking properties. Conventional methods used to create superhydrophobic surfaces include creating a rough structure on a hydrophobic surface or modifying a rough surface by materials with low surface free energy. In many instances, these conventional methods utilize expensive materials or time-consuming procedures to obtain the desired surface properties. Newer, less expensive methods to generate superhydrophobic surfaces will allow this unique property to be more accessible for a multitude of applications. Researchers at the University of California, Irvine have developed a new process to create superhydrophobic surfaces. The method uses only an inexpensive bench-top plasma etcher common to most microfluidic laboratories and achieved superhydrophobic surfaces in PDMS without any chemical modifications. By using this technique, the inventors were able to fabricate a micro droplet array for easy manipulation of liquids. (more...)

Leveraging from microfabrication techniques originally developed for the microelectronics industry, researchers have been able to create simple designs such as well-defined and repetitive patterns of grooves, ridges, pits, and waves.Techniques such as photolithography, electron-beam lithography, colloidal lithography, electrospinning, and nanoimprinting are popular methods for fabricating micro and nano topographical features.However, the need for large capital investments and engineering expertise has prevented the widespread use of these fabrication methods in common biological laboratories.Researchers at the University of California, Irvine have developed an ultra-rapid, robust, and inexpensive fabrication method to create multiscaled grooves, ranging from micron to nanometer in size, as biomimetic cell culture substrates.This method only takes a few minutes to perform and does not require any metal deposition.In addition, the size of the nanowrinkles is easily tuned for a multitude of biological applications. (more...)

Researchers at the University of California, Irvine have developed a novel method to continuously pattern nanofibers on 2D and 3D substrates. A unique polymer ink formulation provides the right balance of viscosity and elasticity necessary to enable controlled, seamless near-field electrospinning of nanofibers at very low voltages. (more...)

Throughout the world, there is a growing need for energy efficient housing solutions. The need is particularly strong in developing countries located in tropical climates, where the cost of energy used for temperature and humidity control is very high. As these climates are often prone to flooding, there is also a need for low-cost, energy efficient emergency housing. The bulk of energy is spent on compensating for heat and cooling losses that occur through the building envelope � the outer shell of a building that protects the indoor environment. Most current building envelopes have separate controls for environmental flows such as humidity, cooling, and light transmission that lack precision and are difficult to calibrate. Climatic self-regulation of building envelopes that can reduce the need for artificial space conditioning is highly relevant to develop. Through a pioneering interdisciplinary collaboration between bioengineering and architecture, researchers at UC Berkeley developed a new sensor technology for external building membranes that can actively respond to environmental changes, and provide automated control of moisture and temperature. The system for Self-Activated Building Envelope Regulation (SABER) is inspired by new understanding of moisture barrier and heat transfer in plants. SABER utilizes optomechanical and hygrothermal sensor/actuator networks build onto a thin film membrane, which can replace the expensive and large mechanical control systems. (more...)

To meet the needs of future power generation and distribution, energy storage devices with both high energy and power density are required; a need not met by current super/ultracapacitors which have very high power density, but energy densities one order less than conventional batteries.  Investigators at University of California at Berkeley have taken an innovative approach to meeting these needs by quantum size effects to substantially boost the particle dielectric constant and breakdown strength.  The investigators use a nanoaggregate/composite with a high K and high breakdown strength in the ultracapcitor in order to achieve both high energy and high power density.  The nanocomposite is created by bonding monodisperse core shell nanoparticles with radii <10 nm in a high breakdown strength polymer (ex. PVDF).  This nanocomposite is integrated into a novel, interdigitated electrode configuration to create batch scale manufacturable ultracapacitor cells with equal or superior energy density to that of lithium ion batteries (100 Wh/kg).  This ultracapacitor modules are being developed for multiple applications from powering portable electronics to hybrid vehicles to energy storage for power plants, especially alternative energy storage (solar, wind, etc.). (more...)

Using the Tacky Dot®, UC San Diego researchers have adapted the technology to the patterning of carbon nanotubes, nanowires, and other types of nano-materials. This technology places the nanomaterials on the surface of the photopolymer, sandwiched with other materials or in layers to form a structure of nanomaterial. The dry method removes both the need for the use of a flux, which is found in wet methods, and the need to anneal the surface to fix the nanomaterials in place. The method is capable of producing patterns whose size is just a few microns. (more...)

In the race for achieving miniaturization of useful machines and devices to the microscale and nanoscale, it would be useful to have a means of connecting components to build devices. One-off production of assemblies of components might be made using laser tweezers or microfluidics, yet it would be highly desirable to assemble millions or billions of copies of the same multicomponent device in solution in parallel at the same time. Heretofore, such massively parallel off-chip assembly processes have been only poorly controlled because the interactions have not been strongly dependent on the nature of the geometry and shape of the components. (more...)

Traditional nanoimprint lithography is a simple and versatile method for producing devices with a large range of possible feature sizes. Within this class of methods, direct nanoimprinting has been used to pattern materials that are suspended in solvents directly, allowing for simple deposition and patterning of materials on substrates with low waste. However, this direct nanoimprinting process inevitably leaves a residual layer that must be etched away in subsequent steps, adding complexity to the process, and often results in features with non-uniform aspect ratios. Investigators at the University of California at Berkeley are addressing these challenges by developing a microfabrication method that allows for the direct patterning of materials on a variety of substrates using microcapillaries. This very simple patterning method results in features with a controllable aspect ratio and zero residual layer. First, a bare solvent or secondary fluid is spread on the substrate. A soft, porous elastomer mold, patterned using traditional photolithography, is pressed on the substrate to pattern the fluid. A nanoparticle ink or other functional or structural material is introduced to the resulting microcapillaries through dedicated filling ports and flows into the microcapillaries as the bare solvent or secondary fluid evaporates though the porous mold. The nanoparticle ink or dissolved material self-concentrates as the solvent evaporates, eventually leaving only the patterned material on the substrate. (more...)

University researchers have designed a novel MEMS vibratory rate gyroscope design, which yields devices robust to fabrication and environmental variations, allows flexible selection of operational parameters, and provides increased bandwidth with minimized sacrifice in gain regardless of the selected frequency of operation.  (more...)

A novel method for Bulk Metallic Glass micro molding using carbon templates obtained from pyrolyzed SU-8 photoresist. (more...)

The most common method for manufacturing polyolefins and their derivatives is by polymerization of olefin monomers with Ziegler-Natta catalysts or by the use of free radical, nucleophilic, or electrophilic initiators. Although one can achieve high molecular weights with these methods, the resulting products are often polydisperse. Many types of polymers are very difficult, if not impossible to manufacture by olefin polymerization. (more...)

The ability to resist nonspecific protein adsorption (protein resistance) is an indicator of a material's biological inertness or biocompatibility. Protein resistant biomaterials such as the commonly used poly(ethylene glycol) (PEG) have been used in a number of applications such as prostheses, contact lenses, implanted devices, microfluidic systems, drug delivery, and substrates for assays. However PEG has two major limitations. First PEG can only be functionalized at the chain ends, and second PEG is not biodegradable. (more...)

Controlling the chemistry of small drops is troublesome owing to the difficulty in handling and metering small volumes. To change the chemistry of a 50nl drop by 10% would require adding or removing a 5nl quantity - very difficult. As a result, most nanovolume assays are set up once and never modified afterwards. Large environmental systems have been built to provide vapor controlled change of chemistry. However, these are far too bulky and inconvenient to be of use to a typical researcher and have seldom been used in nanovolume assays. (more...)

Recent attention has focused on high aspect ratio carbon micro-electromechanical (C-MEMS) because of the many applications possible, such as micro-electrodes in electromechanical sensors and miniaturized energy storage/energy conversion devices. Further, suspended micro/nano carbon structures exhibit a wide electrochemical stability window which makes them interesting for integration in mechanical, electrical, and electromechanical measurements. One of the biggest advantages of suspended micro/nano carbon structures is the high surface to volume ratio.Yet, microfabrication of C-MEMS structures using current processing technology, such as focus ion beam (FIB) and reactive ion etching (RIE) tends to be time consuming and expensive. Low feature resolution, and poor repeatability of the carbon composition as well as the widely varying properties of the resulting devices limits the application of screen printing of commercial carbon inks for C-MEMS. (more...)

Large scale confinement chambers have been created in the past using traditional glass-blowing techniques. However, conventional glass-blowing can only be used to create large components and requires the components to be made one at a time. Micro-glass spheres have previously been fabricated by letting glass particles fall through a temperature-controlled drop tower. While it is possible to create hollow spheres by introducing a blowing agent in the glass, these micro-spheres are not attached to a substrate and are therefore difficult to integrate with micro-machined components on a wafer. (more...)

The ability to deliver drugs locally to the site of need and over a prolonged period of time is important as a therapeutic method for many ailments and diseases. Many drugs are more effective if delivered at a specific site since they can be delivered in concentrated dosages at the point of interest, while maintaining an overall low dosage within the total body. Some drugs require delivery in places that are inconvenient for injection. For example, the highly invasive nature of the treatment and limitations in controlling an effective drug concentration in the eye for age related macular degeneration (AMD) over a prolonged period of time still leave these delivery methods far from ideal. Small, programmable drug delivery implants would be a highly valuable alternative. The current state of art does not provide a satisfactory way to construct a small device that can deliver a time dependent profile of drug dosing. A device that can be readily constructed to produce a desired time dosing profile would be desirable. (more...)