Metalorganic Chemical Vapor Deposition Growth of High-Quality InAs/GaSb Type II Superlattices for Mid-IR Photodetector Applications
X. B. Zhang , A. Petschke, S. Mou , C. Xu , J. H. Ryou , S. L. Chuang , K. C. Hsieh, and R. D. Dupuis 1) Center for Compound Semiconductors and School of Electrical and Computer Engineering, Georgia Institute of Technology, 777 Atlantic Drive NW, Atlanta, GA, 30332-0250, USA 2) Micro and Nanotechnology Laboratory, University of Illinois at Urbana-Champaign, 208 North Wright Street, Urbana, IL 61801, USA
Uncooled InAs-GaSb type-II infrared detectors grown on GaAs substrates for the 8-12-/spl mu/m atmospheric window
We report on the growth and characterization of type-II infrared detectors with an InAs-GaSb superlattice active layer for the 8-12-/spl mu/m atmospheric window at 300 K. The material was grown by molecular beam epitaxy on semi-insulating GaAs substrates. Photoconductive detectors fabricated from the superlattices showed 80% cutoff at about 12 /spl mu/m at room temperature. The responsivity of the device is about 2 mA/W with a 1-V bias (E=5 V/cm) and the maximum measured detectivity of the device is 1.3/spl times/10/sup 8/ cm.Hz/sup 1/2//W at 11 /spl mu/m at room temperature. The detector shows very weak temperature sensitivity. Also, the extracted effective carrier lifetime, /spl tau/=26 ns, is an order of magnitude longer than the carrier lifetime in HgCdTe with similar bandgap and carrier concentration.
Economics of General-Purpose Assembly Robots
Summary A study of the comparative economics of various automatic assembly systems using general-purpose assembly robots is described. In the study, use is made of a “typical” candidate assembly whose profile is obtained from statistical analysis of actual products submitted by interested companies. It is shown that the choice of assembly system and the various parts presentation methods depends on three main factors, namely: the annual production volume per shift, the number of parts in the product and the equipment payback period.