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Proceedings Paper

AlGaN-based photodetectors for solar UV applications
Author(s): Elias Munoz Merino; E. Monroy; Fernando Calle; Miguel A. Sanchez; Enrico Calleja; Franck Omnes; Pierre J. L. Gibart; Francisco Jaque; Inigo Aguirre de Carcer
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Paper Abstract

In the recent years, the depletion of the stratospheric ozone layer has alerted the scientific community about the risks of a solar ultraviolet (UV) radiation overexposure. Biological research has confirmed the very important role of the UV-B (320 - 280 nm) and UV-A (400 - 320 nm) bands on the Earth biosystem. AlxGa1-xN semiconductor alloys, with a bandgap tunable between 3.4 eV and 6.2 eV, are the most suitable materials for the fabrication of solar UV detectors. In this paper we describe the fabrication and characteristics of AlGaN photoconductive and Schottky barrier photodetectors, with Al mole fractions up to 35%. Photoconductive detectors show very high gains, that decrease with increasing incident optical power. They present persistent photoconductivity effects, and a significant below-the-gap response. The physics of this behavior is discussed. On the other hand, AlGaN Schottky barrier photodetectors show a very fast response that is independent of the optical power, and their UV/visible rejection ratio is rather high. As the Al content increases, the evolution of the responsivity and cut-off wavelength is presented. Al0.22Ga0.78N Schottky barriers are very good candidates to monitor the UV-B band. The prospective applications of AlGaN photodiodes to determine the biological action of the solar UV radiation are also discussed.

Paper Details

Date Published: 7 April 1999
PDF: 11 pages
Proc. SPIE 3629, Photodetectors: Materials and Devices IV, (7 April 1999); doi: 10.1117/12.344557
Show Author Affiliations
Elias Munoz Merino, Univ. Politecnica de Madrid (Spain)
E. Monroy, Univ. Politecnica de Madrid (Spain)
Fernando Calle, Univ. Politecnica de Madrid (Spain)
Miguel A. Sanchez, Univ. Politecnica de Madrid (Spain)
Enrico Calleja, Univ. Politecnica de Madrid (Spain)
Franck Omnes, CRHEA-CNRS (France)
Pierre J. L. Gibart, CRHEA-CNRS (France)
Francisco Jaque, Univ. Autonoma de Madrid (Spain)
Inigo Aguirre de Carcer, Univ. Autonoma de Madrid (Spain)

Published in SPIE Proceedings Vol. 3629:
Photodetectors: Materials and Devices IV
Gail J. Brown; Manijeh Razeghi, Editor(s)

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