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Proceedings Paper

Uncooled or minimally cooled 10-µm photodetectors with sub-nanosecond response time
Author(s): Adam Piotrowski; Krzysztof Kłos; Waldemar Gawron; Jarek Pawluczyk; Zbigniew Orman; Józef Piotrowski
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Paper Abstract

We report fast and sensitive long (10 μm) wavelength photodetectors operating at near room temperature. The devices are based on HgCdTe multilayer heterostructures grown by MOCVD on (211) and (111) GaAs substrates. Device-quality heterostructures are obtained without any post growth anneal. The recent improvements of MOCVD growth were: optimized design of the device architecture to increase speed of response, better IMP growth parameters selection taking into account interdiffusion time changes during growth, stoichiometry control during growth by the layer anneal at metal rich vapors during each IMP cycle, precursor delivery to the growth zone monitored with IR gas analyzer, additional metal-rich vapor anneal at the end of growth and passivation of detector structures with wide gap HgCdTe overgrowth deposition. Monolithic optical immersion of the detectors to GaAs microlenses has been applied in purpose to improve performance and reduce RC time constant. The response time of the devices have been characterized using 10μm quantum cascade laser, fast oscilloscope with suitable transimpedance amplifier as a function of detector design, temperature and bias. Detectivity of the best thermoelectrically cooled optically immersed photodiodes approaches 1⋅1010 cmHz1/2/W at ≈10 μm wavelength. The response time of small area decreases with reverse bias to response achieving <100 ps with weak reverse bias.

Paper Details

Date Published: 14 May 2007
PDF: 11 pages
Proc. SPIE 6542, Infrared Technology and Applications XXXIII, 65421B (14 May 2007); doi: 10.1117/12.730230
Show Author Affiliations
Adam Piotrowski, VIGO System S.A. (Poland)
Krzysztof Kłos, VIGO System S.A. (Poland)
Waldemar Gawron, VIGO System S.A. (Poland)
Jarek Pawluczyk, VIGO System S.A. (Poland)
Zbigniew Orman, VIGO System S.A. (Poland)
Józef Piotrowski, VIGO System S.A. (Poland)

Published in SPIE Proceedings Vol. 6542:
Infrared Technology and Applications XXXIII
Bjørn F. Andresen; Gabor F. Fulop; Paul R. Norton, Editor(s)

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