Defense Technical Information Center Compilation Part Notice ADP 015106 TITLE : AlGaAsSb-InGaAsSb-GaSb Epitaxial Hetero structures for Uncooled Infrared Detectors
To order the complete compilation report, use: ADA423729 The component part is provided here to allow users access to individually authored sections f proceedings, annals, symposia, etc. However, the component should be considered within [he context of the overall compilation report and not as a stand-alone technical report. Abstract Lattice matched n-type AlGaAsSb-InGaAsSb-GaSb heterostructures for uncooled infrared detectors including separate absorption and multiplication avalanche photodiodes (SAM-APD) as well as low-voltage InGaAsSb APDs were grown using inexpensive liquid phase epitaxy. Formation of the pn-junction was performed through diffusion of Zn from the vapor phase. Responsivity at X = 2 pm as high as 3.5 A/W was achieved in InGaAsSb APD biased at 8 V with the avalanche multiplication starting at 6 V. Our calculations have shown that the above parameters can result in a NEP value as low as lxl0-2 W or D* value as high as 2x10 10 cm'Hz 1 1 2 /W at room temperature for 400 gim diameter (200 pm diameter photoactive area) APD diodes.
InGaAsSb photovoltaic cells with enhanced open-circuit voltage
Various Zn diffusion profiles in InGaAsSb photovoltaic cells with diffused emitters were experimentally studied. It was determined that strong built-in electric fields near the surface lead to a reduction of the saturation value of the injection (J/sub 01/) component of the dark current, and hence to the increase of the open-circuit voltage (V/sub oc/). A value of J/sub 01/ as low as 4.2/spl times/10/sup -6/ A/cm/sup 2/ and a value of V/sub oc/, as high as 344 mV at 3 A/cm/sup 2/ were measured.
GaInAsSb and InAsSbP photodetectors for mid-infrared wavelengths
Progress on mid-IR photodetectors fabricated by the liquid phase epitaxial growth of GaInAsSb and InAsSbP on GaSb substrates is reported. Both p/n junction and avalanche photodiode structures were fabricated. Preliminary results indicate that these devices can have higher detectivity with lower cooling requirements than commercially available detectors in the same wavelength range. Room temperature detectivity of 1.85 X 108 cmHz1/2/W was measured for GaInAsSb detectors, while room-temperature avalanche multiplication gain of 20 was measured on AlGaAsSb/GaInAsSb avalanche photodiodes. Infrared p/n junction detectors made from GaInAsSb and InAsSbP showed cut-off wavelengths of 2.3 micrometers and 4.4 micrometers respectively.