Eden Prairie, MN, United States

Svt Associates, Inc.

www.svta.com
Eden Prairie, MN, United States
SEARCH FILTERS
Time filter
Source Type

Patent
Svt Associates, Inc. | Date: 2012-08-17

An embodiment of the present invention improves the fabrication and operational characteristics of a type-II superlattice material. Layers of indium arsenide and gallium antimonide comprise the bulk of the superlattice structure. One or more layers of indium antimonide are added to unit cells of the superlattice to provide a further degree of freedom in the design for adjusting the effective bandgap energy of the superlattice. One or more layers of gallium arsenide antimonide are added to unit cells of the superlattice to counterbalance the crystal lattice strain forces introduced by the aforementioned indium antimonide layers.


Patent
Svt Associates, Inc. | Date: 2012-08-17

An embodiment of the present invention improves the fabrication and operational characteristics of a type-II superlattice material. Layers of indium arsenide and gallium antimonide comprise the bulk of the superlattice structure. One or more layers of indium antimonide are added to unit cells of the superlattice to provide a further degree of freedom in the design for adjusting the effective bandgap energy of the superlattice. One or more layers of gallium arsenide antimonide are added to unit cells of the superlattice to counterbalance the crystal lattice strain forces introduced by the aforementioned indium antimonide layers.


Grant
Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase I | Award Amount: 79.92K | Year: 2014

With the advent of electromagnetic and electro-optical sensors in modern military platforms, the issue of detectability extends well beyond that of visible light. The suppression of Electromagnetic Interference/Radio Frequency Interference (EMI/RFI) is considered as one of vital elements of survivability. In general, windows are one of the main sources of EMI/RFI signature. High optical quality windows transparent in 0.4-5µm range are required for shipboard electro-optical sensors. Magnesium aluminate spinel (MgAl2O4) due to the combination of mechanical and optical properties is the material of choice for these windows. At present, EMI/RFI shielding of windows is accomplished using metal grids or conductive transparent coatings which degrade their optical transmission properties. In this program, we propose to develop a robust, transparent coating for efficient EMI/RFI attenuation on spinel windows based on high-conductivity GaN thin films.


Grant
Agency: National Aeronautics and Space Administration | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 124.88K | Year: 2013

SVT Associates proposes an novel type II superlattice structure to extend the cutoff wavelength and CBIRD SL photo diode structure with unipolar barriers to suppress dark current of SL detectors grown on GaSb substrate. This InAs/GaSb superlattice material system is capable of infrared detection in MWIR/LWIR spectral range, depending on layer thickness of each superlattice period. The goal of this program is to develop high performance type II SL based FPA for 5-14 um detection. Photodetector arrays using this material are of great interest to the NASA for various applications including, in particular, imaging and optical detection, and object discrimination when tracking targets in space or performing astronomical observations. These LWIR photo detectors can also find application to infrared-based chemical identification systems and terrestrial mapping. Applying the dark current suppression and cutoff wavelength extension process to the type-II superlattice detectors should result in higher operating temperature, extended cutoff wavelength, and improved quantum efficiency, all important factors that should significantly enhance FPA operation. We intend to characterize the positive effects of proposed techniques in Phase I. In Phase II we will refine the techniques to realize passive-cooled high-performance LWIR FPAs with quantum efficiency larger than 60%.


Grant
Agency: Department of Energy | Branch: | Program: SBIR | Phase: Phase II | Award Amount: 1.00M | Year: 2012

Photocathodes with spin-polarized electron emission are used in physics research. Current photocathodes offer high polarization, but low total currents, and have limited lifetime. Research involving these polarized electrons would be more productive if a higher electron current were provided. This program seeks to increase the delivered polarized electron current from the photocathodes by adding integrated light reflectors to the device structure. These reflectors could concentrate more light energy to the creation of electron current, rather than being wasted as heat in present designs. As a consequence, these photocathodes would also have longer lifetimes. In the Phase I approaches and materials were assayed to best reach the goal of a high current spin polarized photocathode. A prototype design for such a device was developed and deemed feasible for production in a Phase II. The Phase II will fabricate and characterize the device design postulated by the Phase I. As part of the fabrication process several tools will be applied to the growth process to ensure that the end product has the highest chances for success. Spin-polarized electrons have particular application in the field of experimental physics. A subset of this is research into subatomic particles and anti-matter. On a more accessible level such electrons are used in spin polarized low energy electron microscopy, which allows certain materials to be probed to reveal novel properties. At a grander scale polarized electrons also have application to quantum computing and data storage. Spin polarized photocathode, and spin polarized electron source.


Grant
Agency: Department of Energy | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 149.96K | Year: 2012

For several decades photomultiplier tubes (PMTs) have been the main technology for sensitive and low noise detection of photons in many high energy physics experiments. However, compared to solid-state photodetectors, PMTs are bulky, fragile, expensive, and need to be shielded from high magnetic fields and high pressures, which severely limit their application for future DOE projects. Hence, there is a need for high sensitivity photon-counting detectors that can address some of the limitations of PMTs, Our main objective in this program is to develop large area and low-voltage GaN-based avalanche photodiodes (APD) as replacement for bulkier and more fragile PMTs in many applications. We propose to accomplish this goal using a novel technique to virtually eliminate threading dislocations in the active device layer, in order to avoid premature breakdown in these devices. We also propose to investigate multi-quantum well (MQW) AlGaN p-i-n structures that can achieve high-gain and low-noise APD operation at relatively low reverse biases of ~ 10 V. These innovations will allow the fabrication of both photon-counting detectors and large format imaging arrays that can replace PMTs in many scientific, military, and industrial applications, resulting in improved system reliability and robustness, while reducing cost, weight, size and complexity.Commercial Application and Other Benefits: In addition to DOE applications in high energy physics experiments, detection of light in the ultraviolet (UV) spectral range ( & lt;400 nm) has a wide range of commercial, military, and scientific applications. Some examples are UV and space-based astronomy, UV spectroscopy, gamma radiation monitoring in deep well drilling, oil spill monitoring, medical imaging, missile tracking, flame and electric arc sensing, chemical and biological hazard monitoring, and secure optical communications


Grant
Agency: Department of Energy | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 149.88K | Year: 2012

The negative-electron-affinity (NEA) photocathodes which produce polarized electrons are a vital component of electron accelerators such as that at the Stanford Linear Accelerator Center (SLAC). Future systems, such as the International Linear Collider (ILC), will require a polarized electron beam intensity at least 20 times greater than produced by strained GaAs, which is used in the current generation of photocathodes. Additionally, the degree of electron polarization needs to be increased beyond the 75% currently attainable and intrinsic material properties related to improving the surface charge limit must also be addressed, and the photocathodes should be more robust in an RF gun environment. The end result of the combined Phase I Phase II effort will be a new generation of robust photocathodes capable of yielding intense, highly polarized electron beams for use in advanced electron colliders. We have previously achieved & gt; 85% polarization using a strained-superlattice formed from alternating layers of GaAs and GaAsP approximately ten monolayers thick. For this program we will apply a similar superlattice concept utilizing an antimony-based (Sb) material which should overcome material limitations of the GaAs/GaAsP alloys. In the Phase I we will design and fabricate a strained superlattice structure with an antimony-based material by molecular beam epitaxy. The first portion of the program will optimize the growth conditions to achieve the desired alloy composition and interface quality. Photocathode structures will then be fabricated, and their polarization and quantum efficiency will be measured. Commercial Applications: A successful project will produce a highly efficient polarized electron source for use in experimental research at SLAC and other electron collider facilities. These devices have applications in other areas which include magnetic imaging research, surface analysis, Quantum computing and cryptography.


Grant
Agency: Department of Energy | Branch: | Program: SBIR | Phase: Phase II | Award Amount: 999.92K | Year: 2013

The negative-electron-affinity (NEA) photocathodes which produce polarized electrons are a vital component of electron accelerators such as that at DoE Jefferson Lab and the Stanford Linear Accelerator Center (SLAC). Future systems, such as the International Linear Collider (ILC), will require a polarized electron beam intensity at least 20 times greater than produced by strained GaAs, which is used in the current generation of photocathodes. Additionally, the degree of electron polarization needs to be increased beyond the 80% currently attainable and intrinsic material properties related to improving the surface charge limit must also be addressed, and the photocathodes should be more robust in an RF gun environment. The end result of the combined Phase I and Phase II efforts will be a new generation of robust photocathodes capable of yielding intense, highly polarized electron beams for use in advanced electron colliders. We have previously achieved & gt; 85% polarization using a strained superlattice formed from alternating layers of GaAs and GaAsP approximately ten monolayers thick. For this program we will apply a novel superlattice concept utilizing antimony- and arsenic-based material which should overcome material limitations of the GaAs/GaAsP alloys. In Phase I we designed and fabricated an Sb-based strained superlattice structure grown by molecular beam epitaxy. The Phase I program optimized the growth conditions to achieve the desired alloy composition and interface quality. Photocathode structures were fabricated, and their polarization and quantum efficiency were measured at Jefferson Lab. In Phase II, the novel Sb-based SL photocathodes studied in Phase I will be further optimized by investigating parameters that can affect the polarization and quantum efficiency of these photocathodes for high current electron guns. We are also planning further improvement on QE. And finally, the performance of the optimized cathodes will be evaluated in realistic gun environment by Jefferson Lab. Commercial Applications and Other Benefits: A successful project will produce a highly efficient polarized electron source for use in experimental research at DoE Jefferson Lab, SLAC, and other electron collider facilities. These devices have applications in other areas, which include: magnetic imaging research, surface analysis, Quantum computing, and cryptography.


Grant
Agency: Department of Energy | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 149.99K | Year: 2013

The negative-electron-affinity (NEA) photocathodes which produce polarized electrons are a vital component of electron accelerators such as that at the Stanford Linear Accelerator Center (SLAC) and DoE Jefferson Lab. Future systems, such as the International Linear Collider (ILC), will require a polarized electron beam intensity at least 20 times greater than produced by strained GaAs, which is used in the current generation of photocathodes. Additionally, the degree of electron polarization needs to be increased beyond the 75% currently attainable and intrinsic material properties related to improving the surface charge limit must also be addressed, and the photocathodes should be more robust in an RF gun environment. The end result of the combined Phase IPhase II effort will be a new generation of robust photocathodes capable of yielding intense, highly polarized electron beams for use in advanced electron colliders. We have previously achieved & gt;85% polarization using a strained-compensated superlattice formed from alternating layers of GaAsSb and AlGaAsP approximately ten monolayers thick. For this program we will apply a strain-compensation concept utilizing antimony- and phosphorus-based material which should overcome material limitations of the GaAs/GaAsP alloys. In the Phase I we will design and fabricate a strain-compensated superlattice structure with GaAsSb/AlGaAsP material by molecular beam epitaxy. The first portion of the program will optimize the growth conditions to achieve the desired alloy composition and interface quality. Photocathode structures will then be fabricated, and their polarization and quantum efficiency will be measured. Commercial Applications and Other Benefits: A successful project will produce a highly efficient polarized electron source for use in experimental research at SLAC, Jefferson Lab, and other electron collider facilities. These devices have applications in other areas which include magnetic imaging research, surface analysis, Quantum computing and cryptography.


Grant
Agency: Department of Energy | Branch: | Program: SBIR | Phase: Phase II | Award Amount: 999.81K | Year: 2014

The negative-electron-affinity (NEA) photocathodes which produce polarized electrons are a vital component of electron accelerators such as that at DoE Jefferson Lab and the Stanford Linear Accelerator Center (SLAC). Future systems, such as the International Linear Collider (ILC), will require a polarized electron beam intensity at least 20 times greater than produced by strained GaAs, which is used in the current generation of photocathodes. Additionally, the degree of electron polarization needs to be increased beyond the 80% currently attainable and intrinsic material properties related to improving the surface charge limit must also be addressed, and the photocathodes should be more robust in an RF gun environment. The end result of the combined Phase I Phase II effort will be a new generation of robust photocathodes capable of yielding intense, highly polarized electron beams for use in advanced electron colliders. We have previously achieved & gt; 85% polarization using a strained superlattice formed from alternating layers of GaAs and GaAsP approximately ten monolayers thick. For this program we will apply a novel strain- compensated superlattice concept utilizing antimony-, arsenic-, and phosphorus-based material which should overcome material limitations of the GaAs/GaAsP alloys. In the Phase I we designed and fabricated an Sb- and P-based strain-compensated superlattice structure grown by molecular beam epitaxy. The Phase I program optimized the growth conditions to achieve the desired alloy composition and interface quality. Photocathode structures were grown and characterized. Novel Sb-based SL photocathodes studied in Phase I will be further optimized by investigating parameters that can affect the polarization and quantum efficiency of these photocathodes for high current electron guns. Further improvement on QE The performance of the optimized cathodes will be evaluated in realistic gun environment by Jefferson Lab. Commercial Applications and Other Benefits: A successful project will produce a highly efficient polarized electron source for use in experimental research at DoE Jefferson Lab, SLAC, and other electron collider facilities. These devices have applications in other areas which include magnetic imaging research, surface analysis, Quantum computing and cryptography.

Loading Svt Associates, Inc. collaborators
Loading Svt Associates, Inc. collaborators