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A Novel UV Photodetector Array--NZ Applied Technologies, Inc., 14 Gill Street, Woburn, MA 01801-1721; (781) 935-0300
Dr. Yabo LI, Principal Investigator
Ms. Rosemary Koch, Business Official
DOE Grant No. DE-FG02-98ER82629
Amount: $749,910
This project will design and fabricate high sensitivity, ultraviolet (UV) avalanche photodetector (APD) arrays for nuclear physics applications. The arrays will be based on gallium nitride (GaN) and will use state-of-the-art simulation/modeling tools and mature III-V manufacturing processes. Phase I demonstrated the use of lateral epitaxial overgrowth (LEO) by metal organic chemical vapor deposition (MOCVD) for the selective area growth of III-nitrides. The dark current from the GaN Schottky diode arrays was in the range of 8 x 10-9 A (at reverse bias of 15V), and avalanche responsivity of ~ 65/W was achieved (at reverse bias of 40V). GaN 4 by 4 diode arrays with p-i-n structures were also fabricated and characterized. In Phase II, the LEO technology for III-nitride growth will be refined (in order to reduce dislocation density down to 103 cm-2); background impurity levels will be reduced to 1016 cm3; doping controls will be optimized; and high quality p-i-n and heterostructures will be grown. Prototype devices will then be constructed, using theoretical modeling and interactive fabrication runs.
Commercial Applications and other Benefits as described by he awardee: There are numerous commercial applications for highly sensitive, ultraviolet photodetectors and detector arrays, such as CD-ROM, security and medical radiology. This technology should also be useful in automotive, engine and environmental monitoring, as well as engineering damage detection and flame detection.