SBIR 95-1 SOLICITATION

PROJECT SUMMARY

Proposal Number:

08.03-6000

Project Title:

3-5 UM INTLAS DETECTOR ARRAYS WITH MINIMUM COOLING REQUIREMENTS

Technical Abstract:

Spire proposes to demonstrate a new III-V ternary material for high performance, medium wavelength infrared (MWIR 3 to 5 m) detector arrays which can operate under thermo-electric (TE) cooling. Spire proposes to fabricate InTlAs MWIR detectors as an alternative to HgCdTe for TE-cooled infrared focal plane applications. Theoretical calculations suggest that addition of only 5% Tl in InAs can increase the cut-off wavelength from 3.3 m to 4 m at approximately 195K. Spire has already demonstrated that InTlSb films can be grown by metalorganic chemical vapor deposition (MOCVD) and addition of Tl in InSb can reduce the bandgap to 8 m at 300K. For InTlAs, only a very small amount of Tl is required to shift the band edge of InAs to the required spectral response. In addition, InTlAs nearly lattice matches InAs or GaSb, and offers the potential to integrate detector array and read-out circuitry. InTlAs offers many potential advantages over HgCdTe; it has higher mechanical strength, higher quality substrates at lower substrate cost, and better compositional uniformity than HgCdTe. Phase I will establish growth conditions for InTlAs and demonstrate 4 m, photoconductive, IR detectors at 195K. In Phase II, we will fabricate photodiode arrays with Tl-base alloys to demonstrate their potential for MWIR focal plane detectors.

Potential Commercial Applications:

TE-cooled detector arrays based on InTlAs alloys will provide a high performance, yet low cost, replacement for HgCdTe infrared focal plane arrays. In addition to yielding a new class of IR detectors for space-based, industrial, biomedical, and military thermal imaging, this material system will be useful for LEDs or Lasers operating in the mid-wavelength infrared (MWIR) and long- wavelength infrared (LWIR) regions.

Name and Address of Offeror:

Spire Corporation
One Patriots Park
Bedford, MA 01730-2396