NASA SBIR 2005 Solicitation

FORM B - PROPOSAL SUMMARY


PROPOSAL NUMBER:05 S2.04-8023
SUBTOPIC TITLE:Deep Space Power Systems
PROPOSAL TITLE:High Operating Temperature, Radiation-Hard MIM Thermophotovoltaic Converters

SMALL BUSINESS CONCERN (Firm Name, Mail Address, City/State/Zip, Phone)
Spire Corp
One Patriots Park
Bedford ,MA 01730 - 2396
(781) 275 - 6000

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Steven J. Wojtczuk
swojtczuk@bandwidthsemi.com
One Patriots Park
Bedford, MA  01730 -2396
(781) 275 - 6000

TECHNICAL ABSTRACT (LIMIT 200 WORDS)
Spire Corporation proposes to investigate InGaAs thermophotovoltaic (TPV) cells optimized for high temperature operation (~150C) and radiation hardness against the 1.64MeV neutron flux likely from plutonium dioxide general purpose heat sources. We propose to develop a temperature-dependent TPV cell model and select an optimum bandgap for 150C operation with a 1100C heat spectrum, using a cell design with a thin (~1 micron vs standard ~3 micron) base that improves tolerance to diffusion length degradation from radiation. In order to increase photon absorption in this thin cell, we propose to epitaxially grow a monolithic 15 period InGaAs/InAlAs Bragg mirror to reflect about 90% of the incident usable (2 ~micron wavelength) photons back through the cell. The proposed advantage of the Bragg over a standard back metal mirror reflector is that the dielectric mirror has some ability to use strain exerted at the interfaces of the different mirror materials as a threading-to-misfit dislocation filter to further enhance the cell efficiency. We also propose to examine polyimide along with standard SiN for MIMs (monolithically integrated multijunction module) edge passivation.

POTENTIAL NASA COMMERCIAL APPLICATIONS (LIMIT 150 WORDS)
Deep space missions to the outer planets may use radioisotope heat sources to supply power to the probe. Thermoelectrics have been used in the past, and thermophotovoltaic technology has been proposed as a higher (~3-4X) efficiency replacement for these thermoelectric converters.

POTENTIAL NON-NASA COMMERCIAL APPLICATIONS (LIMIT 150 WORDS)
Co-generation to deliver heat and electrical power from thermophotovoltaics has been proposed as a potentially important technology for isolated rural dwellings in locations such as Alaska, where a large part of the population is remote and off the power grid.

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.

TECHNOLOGY TAXONOMY MAPPING
Thermoelectric Conversion


Form Printed on 09-19-05 13:12