NASA SBIR 2006 Solicitation


SUBTOPIC TITLE:Detector Technologies for UV, X-Ray, Gamma-Ray and Cosmic-Ray Instruments
PROPOSAL TITLE:Quantum Calorimeters Based on HgCdTe Alloys

SMALL BUSINESS CONCERN (Firm Name, Mail Address, City/State/Zip, Phone)
EPIR Technologies Inc
590 Territorial Drive, Suite B
Bolingbrook, IL 60440-4881
(630) 771-0201

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Christoph   Grein
590 Territorial Drive, Suite B
Bolingbrook, IL  60440-4881
(630) 771-0203

TECHNICAL ABSTRACT ( Limit 2000 characters, approximately 200 words)
NASA's next generation of x-ray observation missions require x-ray calorimeters with superior energy resolution. Semimetallic HgTe has already proven itself as an excellent soft x-ray absorber material due to its low heat capacity. The alloy Hg0.834Cd0.166Te is predicted to also have zero energy gap at T=0 K and a heat capacity even less that that of HgTe due to: (i) a greater Debye temperature (resulting in a lower lattice heat capacity), and (ii) a smaller electron effective mass (resulting in a lower electronic heat capacity). Thus Hg0.834Cd0.166Te-based microcalorimeter arrays are expected to have an energy resolution superior to that of HgTe-based ones. We propose the growth of single crystal Hg0.834Cd0.166Te layers by molecular beam epitaxy on Si substrates. Mercury vacancies will be filled after growth to reduce the possibility of them acting as acceptors and introducing a significant electronic heat capacity. The Hg0.834Cd0.166Te layers will be characterized by x-ray diffraction to asses their structural quality and crystallinity, FTIR mapping to confirm the uniformity of their energy gaps and alloy compositions, Hall measurements to assess their electrical transport properties, etch pit density
counts to determine dislocation densities, transmission electron microscopy to determine microscopic structural information, and heat capacity measurements at mK temperatures to test their promise as high energy resolution quantum calorimeters.

POTENTIAL NASA COMMERCIAL APPLICATIONS ( Limit 1500 characters, approximately 150 words)
The principal application will be as next-generation soft x-ray calorimeters for astrophysical observations. The material system to be developed under this program, Hg1-xCdxTe/Si with x=0.166, promises high x-ray energy resolutions and benefits from well-established device and array processing technology (already developed for infrared arrays with x>0.166). Hence the fabrication of large (greater than 1000 pixel) arrays is feasible with energy and spatial resolutions superior to the current state of the art. Achieving heat capacities lower than HgTe would also make high resolution microcalorimeters more feasible for hard X-ray and gamma-ray instruments, where much thicker absorbers are required.

POTENTIAL NON-NASA COMMERCIAL APPLICATIONS ( Limit 1500 characters, approximately 150 words)
Soft x-ray calorimeters have several industrial applications including X-ray microanalysis and ground-based scientific instrumentation, for example in the fields of laboratory atomic physics and the analysis of biological materials at synchrotrons. The materials to be developed under this program also have broad ranging applications in the defense and commercial markets. Specifically, Hg1-xCdxTe/Si with x>0.166 material is of great importance to the US infrared focal plane array industry that desires the lower costs, higher formats and greater mechanical robustness that Si substrates provide. Applications include night vision; daytime navigation aids in the presence of fog and other atmospheric obscurants; sensors for manufacturing quality control and nondestructive evaluation; medical applications such as non-invasive thermal imaging for the diagnosis of cancer and other life-threatening diseases; environmental monitoring; drug and law enforcement; and search and rescue.

NASA's technology taxonomy has been developed by the SBIR-STTR program to disseminate awareness of proposed and awarded R/R&D in the agency. It is a listing of over 100 technologies, sorted into broad categories, of interest to NASA.

Semi-Conductors/Solid State Device Materials

Form Printed on 09-08-06 18:19