Sharp Bandpass AlGaN p-i-n Photodiode Detectors for Ultraviolet B Irradiance Measurements

50521-98-I 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. Peter P. Chow, Business Official DOE Grant No. DE-FG02-98ER82683 Amount: $74,895 Solar radiation in the ultraviolet B (280-320 nm) band is attenuated by ozone absorption in the upper atmosphere, and monitoring this band is important to understanding the dynamics of the earth¿s atmosphere and warning of potential health risks arising from high exposure to short wavelength solar radiation. A low cost, robust, highly accurate photodiode bandpass detector is needed for irradiance measurements in this part of the solar spectrum. This project will use p-i-n photodiodes fabricated from the wide band-gap semiconductor aluminum gallium nitride, AlxGa(1-x)N, as the ultraviolet sensitive detector for these measurements. A short wavelength absorbing, but electrically non-active, overlayer will be incorporated directly into the photodiode structure to create a narrow bandpass spectral response in the ultraviolet B region. Such a device will have high quantum efficiency response within the bandpass and ~105 rejection of radiation outside the bandpass. The objective of the Phase I effort is to fabricate a nitride-based photodiode detector which is sensitive to the ultraviolet B band and has high rejection of response to all other wavelengths. Commercial Applications and Other Benefits as described by the awardee: The technology should also be applicable in chemical analysis, combustion diagnostics, water quality assurance, medical diagnostics, and in the semiconductor industry. Military applications, (e.g., missile detection and artillery fire detection) are also possible._