249 research outputs found

    NASA SBIR abstracts of 1991 phase 1 projects

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    The objectives of 301 projects placed under contract by the Small Business Innovation Research (SBIR) program of the National Aeronautics and Space Administration (NASA) are described. These projects were selected competitively from among proposals submitted to NASA in response to the 1991 SBIR Program Solicitation. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 301, in order of its appearance in the body of the report. Appendixes to provide additional information about the SBIR program and permit cross-reference of the 1991 Phase 1 projects by company name, location by state, principal investigator, NASA Field Center responsible for management of each project, and NASA contract number are included

    Characterizationn of Polumer-Based MEMS Pyroelectic Infrared Detector

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    AFRL/MLPJE had developed a novel thermal sensing material termed protein-impregnated-polymer (PIP). Thus far, a proof-of-concept has been demonstrated using a macro-sized pixel (0.64 mm2) as a bolometric detector. In an effort to better characterize this novel thermal sensing material, experimental data was used to determine figures of merit (FOMs) comparative to off-the-shelf thermal detectors. Microelectromechanical (MEMS) pixels were designed and used as the support structure for an inkjet-deposited droplet of the PIP. During the material characterization, two observations were made: PIP is a pyroelectric material, and the polymer (polyvinyl alcohol (PVA)) without the protein was found to be more suited for measurements taken on the micro-scaled pixels. Both PVA and PVA doped with carbon black (PVA-CB) were the materials focused on in this research, with the latter being the material used for FOM characterization. Pyroelectric coefficients for PVA and PVA-CB were found to be 755.11 nC/(cm2 K), and 108.32 nC/(cm2 K), respectively, which are both two orders of magnitude higher than values for current pyroelectric polymers. A responsivity of 1.66 x 104 V/W, thermal time constant of 3.59 sec, noise equivalent power of 21.3 nW, and a detectivity of 1.93 x 105 cm √Hz/W were the FOMs found in this thesis. Although the calculated FOMs are not stellar in comparison to current thermal detector technology, this material shows much promise. The shortfalls in FOMs could potentially be attributed to a poor pixel design. This thesis plants the scientific seed in cultivating a thermal imaging focal plane array (FPA) using a newly found pyroelectric polymer

    The NASA SBIR product catalog

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    The purpose of this catalog is to assist small business firms in making the community aware of products emerging from their efforts in the Small Business Innovation Research (SBIR) program. It contains descriptions of some products that have advanced into Phase 3 and others that are identified as prospective products. Both lists of products in this catalog are based on information supplied by NASA SBIR contractors in responding to an invitation to be represented in this document. Generally, all products suggested by the small firms were included in order to meet the goals of information exchange for SBIR results. Of the 444 SBIR contractors NASA queried, 137 provided information on 219 products. The catalog presents the product information in the technology areas listed in the table of contents. Within each area, the products are listed in alphabetical order by product name and are given identifying numbers. Also included is an alphabetical listing of the companies that have products described. This listing cross-references the product list and provides information on the business activity of each firm. In addition, there are three indexes: one a list of firms by states, one that lists the products according to NASA Centers that managed the SBIR projects, and one that lists the products by the relevant Technical Topics utilized in NASA's annual program solicitation under which each SBIR project was selected

    Pyroelectric and electrocaloric effects in hafnium oxide thin films

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    The material class of hafnium oxide-based ferroelectrics adds an unexpected and huge momentum to the long-known phenomenon of pyroelectricity. In this thesis, a comprehensive study of pyroelectric and electrocaloric properties of this novel ferroelectric material class is conducted. hafnium oxide is a lead-free, non-toxic transition metal oxide, and abundant in the manufacturing of semiconductor devices. The compatibility to existing fabrication processes spawns the possibility of on-chip infrared sensing, energy harvesting, and refrigeration solutions, for which this dissertation aims to lay a foundation. A screening of the material system with respect to several dopants reveals an enhanced pyroelectric response at the morphotropic phase boundary between the polar orthorhombic and the non-polar tetragonal phase. Further, a strong pyroelectric effect is observed when applying an electric field to antiferroelectric-like films, which is attributed to a field-induced transition between the tetragonal and orthorhombic phases. Primary and secondary pyroelectric effects are separated using high-frequency temperature cycles, where the effect of frequency-dependent substrate clamping is exploited. The piezoelectric response is determined by comparing primary and secondary pyroelectric coefficients, which reproduces the expected wake-up behavior in hafnium oxide films. Further, the potential of hafnium oxide for thermal-electric energy conversion is explored. The electrocaloric temperature change of only 20 nm thick films is observed directly by using a specialized test structure. By comparing the magnitude of the effect to the pyroelectric response, it is concluded that defect charges have an important impact on the electrocaloric effect in hafnium oxide-based ferroelectrics. Energy harvesting with a conformal hafnium oxide film on a porous, nano-patterned substrate is performed, which enhances the power output. Further, the integration of a pyroelectric energy harvesting device in a microchip for waste heat recovery and more energy-efficient electronic devices is demonstrated. High dielectric breakdown fields of up to 4 MV/cm in combination with a sizable pyroelectric response and a comparably low dielectric permittivity illustrate the prospect of hafnium oxide-based devices for future energy conversion applications

    Bolometers

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    Infrared Detectors and technologies are very important for a wide range of applications, not only for Military but also for various civilian applications. Comparatively fast bolometers can provide large quantities of low cost devices opening up a new era in infrared technologies. This book deals with various aspects of bolometer developments. It covers bolometer material aspects, different types of bolometers, performance limitations, applications and future trends. The chapters in this book will be useful for senior researchers as well as beginning graduate students

    Innovative Long Wavelength Infrared Detector Workshop Proceedings

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    The focus of the workshop was on innovative long wavelength (lambda less than 17 microns) infrared (LWIR) detectors with the potential of meeting future NASA and DoD long-duration space application needs. Requirements are for focal plane arrays which operate near 65K using active refrigeration with mission lifetimes of five to ten years. The workshop addressed innovative concepts, new material systems, novel device physics, and current progress in relation to benchmark technology. It also provided a forum for discussion of performance characterization, producibility, reliability, and fundamental limitations of device physics. It covered the status of the incumbent HgCdTe technology, which shows encouraging progress towards LWIR arrays, and provided a snapshot of research and development in several new contender technologies

    Gallium Nitride Resonators for Infrared Detector Arrays and Resonant Acoustoelectric Amplifiers.

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    This work presents the first comprehensive utilization of Gallium Nitride (GaN) in high-performance, high-frequency micromechanical resonators. It presents characterization of critical electromechanical properties of GaN and validation of high-performance designs. The primary motivation behind this project is the use of GaN resonators as sensitive, low-noise, uncooled infrared (IR) detectors. IR response of micromechanical resonators is based on radiative absorption and a consequent shift in its resonant frequency. Mechanical resonators are expected to perform better than contemporary uncooled IR detectors as the noise equivalent temperature difference (NETD) is primarily limited by each resonator’s thermomechanical noise, which is smaller than resistive bolometers. GaN is an ideal material for resonant IR detection as it combines piezoelectric, pyroelectric, and electrostrictive properties that lead to a high IR sensitivity up to -2000 ppm/K (~ 100× higher than other materials). To further improve IR absorption efficiency, we developed two thin-film absorbers: a carbon nanotube (CNT)-polymer nanocomposite material with broad-spectrum absorption efficiency (> 95%) and a plasmonic absorber with narrow-spectrum absorption (> 45% for a select wavelength) integrated on the resonator. Designs have also been successfully implemented using GaN-on-Si, aluminum nitride (AlN), AlN-on-Si, and lead-zirconate-titanate (PZT), and fabricated both in-house and using commercial foundry processes. Resonant IR detectors, sense-reference pairs, and small-format arrays (16 elements) are successfully implemented with NETD values of 10 mK, and ~1 ms-10 ms response times. This work also presents the first measurements and analysis of an exciting, fairly unexplored phenomenon: the amplification of acoustic standing waves in GaN resonators using electrical energy, boosting the quality factor (Q) and reducing energy losses in the resonator. This phenomenon is based on phonon-electron interactions in piezoelectric semiconductors. Under normal conditions this interaction is a loss mechanism for acoustic energy, but as we discovered and consistently demonstrated, it can be reversed to provide acoustoelectric amplification (resulting in Q-amplification of up to 35%). We present corroborated analytical and experimental results that describe the phonon-electron loss/gain in context with other loss mechanisms in piezoelectric semiconductor resonators. Research into this effect can potentially yield insights into fundamental solid-state physics and lead to a new class of acoustoelectric resonant amplifiers.PhDElectrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/108759/1/vikrantg_1.pd

    The 2017 Terahertz Science and Technology Roadmap

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    Science and technologies based on terahertz frequency electromagnetic radiation (100GHz-30THz) have developed rapidly over the last 30 years. For most of the 20th century, terahertz radiation, then referred to as sub-millimeter wave or far-infrared radiation, was mainly utilized by astronomers and some spectroscopists. Following the development of laser based terahertz time-domain spectroscopy in the 1980s and 1990s the field of THz science and technology expanded rapidly, to the extent that it now touches many areas from fundamental science to “real world” applications. For example THz radiation is being used to optimize materials for new solar cells, and may also be a key technology for the next generation of airport security scanners. While the field was emerging it was possible to keep track of all new developments, however now the field has grown so much that it is increasingly difficult to follow the diverse range of new discoveries and applications that are appearing. At this point in time, when the field of THz science and technology is moving from an emerging to a more established and interdisciplinary field, it is apt to present a roadmap to help identify the breadth and future directions of the field. The aim of this roadmap is to present a snapshot of the present state of THz science and technology in 2016, and provide an opinion on the challenges and opportunities that the future holds. To be able to achieve this aim, we have invited a group of international experts to write 17 sections that cover most of the key areas of THz Science and Technology. We hope that The 2016 Roadmap on THz Science and Technology will prove to be a useful resource by providing a wide ranging introduction to the capabilities of THz radiation for those outside or just entering the field as well as providing perspective and breadth for those who are well established. We also feel that this review should serve as a useful guide for government and funding agencies

    5th International Symposium Technologies for Polymer Electronics - TPE 12: 22. - 24. May 2012, Rudolstadt/Germany ; Proceedings

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