Development of the III-V Barrier PhotoDetector Heterostructures for Spectral Range Above 10 microns
Final rept. 1 Sep 2012-31 Aug 2015
STATE UNIV OF NEW YORK AT STONY BROOK
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Novel approach to growth of quality narrow gap InAsSb-based materials using metamorphic buffers on GaSb substrates was pursued. The developed GaInSb and AlInSb graded buffers served as a platform for growth of strain-free low-dislocation-density bulk InAsSb layers. The ability to select the lattice constant up to 3 greater than that of GaSb eliminated the lattice constant design constrain in the realization of III-V narrow gap semiconductors grown pseudomorphically on the available substrates. The buffers were developed for InAsSb alloys with Sb compositions in the range from 20 to 65 . The bulk InAsSb layers showed the energy gaps as low as 90 meV at 77 K. nBn and nBp barrier heterostructures with bulk InAsSb absorbers showed high quantum efficiency consistent with the fundamental absorption, efficient hole transport and long carrier lifetime of Ga-free materials. Barrier heterostructures with undoped InAsSb absorbers showed no surface current. The fundamental absorber parameters were determined from transient response of barrier heterostructures to pulsed excitation. Feasibility of the extension of the absorption edge of InAsSb-based materials grown on metamorphic buffers to longer wavelengths preserving minority hole transport was demonstrated experimentally using short-period strained layer superlattices obtained by modulation of Sb composition.
- Physical Chemistry
- Optical Detection and Detectors