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.
Study of Zn diffusion into GaSb from the vapour and liquid phase
Abstract In order to develop a simple and reproducible method to fabricate p-n structures on GaSb for optoelectronic devices, the Zn-diffusion into n-doped GaSb substrates was studied. Two methods of Zn-diffusion were experimentally investigated: (a) diffusion from the vapour phase in a pseudo-closed box system and (b) diffusion from the liquid phase from a Ga-Sb-Zn melt. The process parameters, which provide good control over Zn surface concentration and p-n junction depth, were determined.
Effect of stress conditions on collapse deformation behavior of a rockfill material
A set of saturated and dry-saturated large-scale triaxial tests were conducted in order to explore the effects of stress conditions on the saturation-induced collapse deformation behavior of a rockfill material. Specimens were tested in different confining pressures and for dry-saturated tests the specimens were submerged in various shear stress levels. The results indicate that in all of the dry-saturated tests a sudden reduction in the volume of the specimens was observed during the submerging process. The ratio of the minimum axial strength of a submerged specimen (at the end of the saturation process) to the shear strength of the specimen before saturation is defined as the coefficient of stress recovery, Csr. Results of the dry-saturated tests showed that this ratio increases as the confining pressure increases and decreases by increasing the shear stress level. According to the results of dry-saturated tests the values of internal friction angle reduction caused by saturation (Δϕc), the ratio of the elasticity modulus of the material after saturation to its elasticity modulus in dry condition, i.e., Ewet/Edry, and also the saturation induced sudden volumetric strain (εvc) decrease as the confining pressure increases. However the shear stress level does not have any meaningful effect on the variation of Dfc, Ewet/Edry and (εvc).