Voltage-tunable dual-band Ge/Si photodetector operating in VIS and NIR spectral range

Extending and controlling the spectral range of light detectors is very appealing for several sensing and imaging applications. Here we report on a normal incidence dual band photodetector operating in the visible and near infrared with a bias tunable spectral response. The device architecture is a...

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Bibliographic Details
Published in:Optics express 2019-03, Vol.27 (6), p.8529-8539
Main Authors: Simola, E Talamas, De Iacovo, A, Frigerio, J, Ballabio, A, Fabbri, A, Isella, G, Colace, L
Format: Article
Language:English
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Summary:Extending and controlling the spectral range of light detectors is very appealing for several sensing and imaging applications. Here we report on a normal incidence dual band photodetector operating in the visible and near infrared with a bias tunable spectral response. The device architecture is a germanium on silicon epitaxial structure made of two back-to-back connected photodiodes. The photodetectors show a broad photoresponse extending from 390nm to 1600nm with the capability to electronically select the shorter (400-1100 nm) or the longer (1000-1600 nm) portion with a relatively low applied voltage. Devices exhibit peak VIS and NIR responsivities of 0.33 and 0.63 A/W, respectively, a low optical crosstalk (120dB) and, thanks to their low voltage operation, maximum specific detectivities of 7·10 cmHz /W and 2·10 cmHz /W in the VIS and NIR, respectively.
ISSN:1094-4087
1094-4087
DOI:10.1364/OE.27.008529