SBIR 95-1 SOLICITATION
2 TO 3 MICRON INGAAS DETECTOR ARRAYS
The 1.5 to 2.5 m spectral range is important for differential
absorption LIDAR (DIAL) measurements of various atmospheric gases.
Indium gallium arsenide (InXGa1-XAs) is an ideal optoelectronic
material for this spectral range. The InXGa1-XAs bandgap can be
varied from 1.42 eV (0.87 m cutoff wavelength) to 0.36 eV (3.4 m)
at the time of epitaxial material growth by changing indium
composition in the InxGa1-xAs compound, so that the cells can be
"tuned" to various emission spectra. Without special techniques,
the lowest dark current (lowest noise) is achieved only at the
0.74 eV (1.7 m) In0.53Ga0.47As composition that is lattice-matched to
the InP substrate wafer. However, Spire has sold thousands of
high-performance, lattice-mismatched, 2.3 m InxGa1-xAs photovoltaic
cells for use in thermophotovoltaic power conversion by using
grading layer techniques to accommodate the lattice mismatch
between the InXGa1-XAs and InP. Although these power converter cells
have low dark currents, low series resistance (~0.05_) and quantum
efficiencies of 90% at 2.3 m, photodiodes require lower doping
levels to minimize capacitance and enhance the frequency response
(speed). This program seeks to apply Spire_s very successful
commercial InXGa1-XAs power converter technology to InGaAs
photodiodes and arrays.
Potential Commercial Applications:
InGaAs photodiodes operating at 2 to 3 m will be useful as single
element detectors for radiometric and heterodyne applications.
Long linear arrays could be used for sensors in grating
spectroscopy instruments, and two dimensional focal plane arrays
would be useful for near IR imaging.
Name and Address of Offeror:
One Patriots Park
Bedford, MA 01730-2396
Small Business Innovation Research Program (SBIR) &
Small Business Technology Transfer Program (STTR) Programs
Electronic Management System (EMS)
National Aeronautics and Space Administration (NASA)
The SBIR/STTR EMS site is maintained by Steve
Hu, Hughes STX.
For comments and questions, contact
Updated: Feb. 7, 1996