Volume 12, Number 2 2005 Opportunity for Partnership
Micron- and submicron-sized pointed structures are used in electrical and mechanical equipment applications where sharp tips are needed. However, existing methods to produce these structures—materials synthesis and etching—are plagued with difficulties. The equipment (e.g., deep reactive ion etching) can be very expensive, and the resulting arrays are small with tips/cones of varying heights and aspect ratios. However, a researcher at NASA Goddard Space Flight Center has developed a new, cost-effective process for producing large numbers of uniform point structures. This innovative process involves dropping or spinning a ferrofluid (i.e., a liquid containing Fe2O3 particles) onto a glass, quartz, or other substrate. A magnetic field is then applied using simple permanent or electro-magnets, causing the ferrofluid to form pointed structures that are uniformly aligned with a maximized aspect ratio. The ferrofluid then is dried at room temperature. The result is a template that can serve as a substrate for subsequent film growth through any standard thin-film deposition technique, including evaporation, sputtering or chemical vapor deposition. Templates have survived vacuum testing at 10–6 Torr. The conformal films applied to the template will reflect its pointed structure. NASA’s ferrofluid technique may be particularly useful for creating emitters to be coated by wide bandgap semiconductors, which can absorb and emit electrons in the ultraviolet light bands. These materials, such as readily available ZnO, are an excellent alternative for the traditional large, high-voltage photocathode systems. Coating the templates created with Goddard’s technology with ZnO or other oxides avoids the oxidizing properties associated with metals typically used in photocathodes (e.g., tungsten, chromium). Therefore, the photocathodes are less susceptible to contamination, decay and radiation damage, and may be more chemically and structurally stable. This technology is expected to provide a low-cost electron source useful in a wide range of electronics and mechanical equipment applications such as field emission displays, field emission devices, photocathodes, scanning tunneling microscopes, atomic force microscopes, far ultraviolet (UV) photolithography and low-power propulsion systems. The benefits of this innovation include the following:
For more information, contact NASA Goddard’s Office of Technology Transfer, (301) 286-2642, techtransfer@gsfc.nasa.gov. Please mention that you read about it in Technology Innovation The Revolutionary TETwalker NASA Goddard Space Flight Center offers the opportunity to partner in the further development of this innovative technology for use in robotics and other applications requiring extreme mobility and adaptability in varied environments. The TETwalker represents a revolutionary idea in robotics and structural architecture. It is a creative application of Addressable Reconfigurable Technology (ART), developed by NASA researchers at Goddard Space Flight Center working jointly with Langley Research Center. This highly integrated three-dimensional mesh of actuators and structural elements has the potential to autonomously change form to optimize its function, reconfigure into specific tools, and perform tasks in a wide range of terrain and environment. This is the first element in the development of a synthetic skeletal muscular and skin system to be controlled by a synthetic neural system. The tetrahedron module is configured using readily available, addressable, electromechanical components. Lightweight telescoping struts are attached at each end to pivoting nodes to allow movement over a wide range of angles. Motors within the nodes control the telescoping struts, allowing specific sections of the tetrahedron to lengthen or shorten, changing its center of mass. This enables the tetrahedron to maneuver in a controlled flip-flop motion by toppling over in alternating directions. By grouping multiple tetrahedra, many degrees of freedom/function and much smoother locomotion are possible, including the formation of flattened and conformable surfaces (e.g., draping over obstacles) as well as slithering, rolling and amoeboid/caterpillar-like motions. Independent shaping of the top and bottom interconnected nodes is also possible, to allow reconfiguration for multiple complex functions, such as forming tools and for communications. Benefits of the innovation include:
Future developments will reduce size using Micro-Electro-Mechanical Systems (MEMS) and then further using Nano-Electro-Mechanical Systems (NEMS). With this refinement, even greater control and agility will be possible. Potential applications for the technology include the following:
Please mention that you read about it in Technology Innovation. |
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