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Sharp Bandpass AlGaN P-I-N Photodiode Detectors for Ultraviolet B Irradiance Measurements--SVT Associates, Inc., 7620 Executive Drive, Eden Prairie, MN 55344-3677; 612-934-2100
Dr. Jody J. Klaassen, Principal Investigator
Dr. Shelly Harris, Business Official
DOE Grant No. DE-FG02-98ER82683
Amount: $749,966
An advanced sensing technology is being developed for ultraviolet B (UVB) irradiance measurements that exceeds the capabilities of standard sensors in performance, reliability, versatility, and price. This new technology involves a family of ultraviolet-sensitive, photodiode detectors fabricated from the group III-nitride semiconductor material, aluminum gallium nitride (AlGaN). The material composition and device structure of AlGaN photodiodes can be "tuned" to create narrow bandpass (<10 nm) detectors that cover the entire range of UVB, 280-320 nm, and the longer wavelength UVA range, to 365 nm. In Phase I, proof-of-principle was demonstrated using a bandpass AlGaN photodiode covering the UVB spectral range. Sharp bandpass photodiode detectors, having out-of-band rejection levels comparable to double cavity interference filters, were also demonstrated. Phase II will (1) create an AlGaN, UVB sensor, which mimics the response of the standard UVB sensor--such a device will allow continuity with past observations and is much smaller and far less expensive than standard sensors; (2) create an AlGaN-based sensor that is an exact match to the standard, human, erythemal response, action spectrum--this device would be valuable for personal exposure monitors; and (3) develop a series of high stability, high efficiency, bandpass (<10nm), photodiode detectors, at 305, 317, 325, 332, and 369 nm, for use in multi-filter instruments.
Commercial Applications and other Benefits as described by the awardee: Personal, UV exposure meters would be an immediate commercial market for this technology. Other applications include industrial situations where accurate measurements of intense UV radiation is necessary, such as for UV photolithography in the semiconductor industry, UV curing applications in industries such as automotive and plastics, and germicidal sterilization applications in the medical and pharmaceutical fields.