Form 9.B Project Summary

Chron: 971941

Proposal Number: 10.02-2100A

Project Title: Miniature, Semiconductor, Sharp Bandpass Detector for Biological Fluorescence Detection

Technical Abstract (Limit 200 words)

In this Phase I SBIR project wide band-gap semiconductor p-i-n photodiodes with sharp bandpass responsivity will be developed for use in ultraviolet fluorescence detection of biological contamination of high purity water systems. AlxGa1-xN, grown by molecular beam epitaxy (MBE) will be used to fabricate photodiodes having high quantum efficiency spectral response in the ultraviolet. The innovation in this proposal is to combine a short wavelength absorbing, electrically non-active overlayer with the electrically active p-i-n structure photodiode to produce a sharp bandpass photodetector. Such a device will have near quantum efficiency response inside the bandpass and ~105 rejection of radiation outside the bandpass. The sensor will allow replacement of

fragile and power hungry photomultiplier tubes currently used for fluorescence detection. The all semiconductor, ultraviolet sensitive photodiode for biological fluorescence detection will be compact, rugged, and low power consuming, which are important attributes for sensors on manned space missions. For the Phase I project, the essential amino acids tryptophan and tyrosine will be evaluated as model systems for biological detection. Tryptophan and tyrosine are present in nearly all proteins, and their detection can be used as a warning of biological contamination. Both of these amino acids can be excited by the 254 nm line of mercury discharge lamps commonly used for sterilization of high purity water systems.

Potential Commercial Applications (Limit 200 words)

Miniature semiconductor photodiodes for biological fluorescence detection will have applications in water quality assurance testing, in-situ monitoring of bio-reactions, and in bio-analysis.

Name and Address of Principal Investigator (Name,

Organization Name, Mail Address, City/State/Zip)

Jody J. Klaassen

SvT Associates, Inc.

7620 Executive Drive

Eden Prairie , MN 55344

Name and Address of Offeror (Firm Name, Mail Address,


Peter P. Chow

SVT Associates, Inc.

7620 Executive Drive

Eden Prairie , MN 55344