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Narrow‐band photodetection based on M ‐plane GaN films
Author(s) -
Ghosh Sandip,
Rivera C.,
Pau J. L.,
Muñoz E.,
Brandt O.,
Grahn H. T.
Publication year - 2008
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200778650
Subject(s) - photodetector , responsivity , photodetection , optoelectronics , materials science , optics , planar , physics , computer graphics (images) , computer science
Rapid identification of a range of hazardous airborne biological and chemical agents requires simultaneous detection at several specific wavelengths, and consequently a set of photodetectors with very narrow‐band spectral responsivity. We demonstrate two ultraviolet photodetection configurations based on strained M ‐plane GaN films on LiAlO 2 (100) substrates grown by molecular‐beam epitaxy with a detection bandwidth below 8 nm. The optical band gap of the film depends on the orientation of the linear polarization of the incident light relative to the c ‐axis of GaN, which lies in the film plane. The first configuration consists of a polarization‐sensitive planar Schottky photodetector and a filter. An orthogonal alignment of the c ‐axis of the photodetector and the filter produces a detection system with a peak responsivity at 360 nm and a bandwidth of 6 nm. The second one consists of two planar Schottky photodetectors with their c ‐axes oriented perpendicular to each other. The difference signal between the two photodetectors produces a peak responsivity at 358 nm and a bandwidth of 7.3 nm. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)