Citation
Ghosh, Sandip and Rivera de Lucas, Carlos and Pau, J.L. and Muñoz Merino, Elias and Brandt, Oliver and Grahn, H.T.
(2008).
Narrow-band photodetection based on M-plane GaN films.
"Physica Status Solidi A - Applications and Materials Science", v. 205
(n. 5);
pp. 1100-1102.
ISSN 0031-8965.
https://doi.org/10.1002/pssa.200778650.
Abstract
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 LiAlO2(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 polarizationsensitive 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.
