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

E Talamas Simola; A De Iacovo; J Frigerio; A Ballabio; A Fabbri; G Isella; L Colace

doi:10.1364/OE.27.008529

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

Opt Express. 2019 Mar 18;27(6):8529-8539. doi: 10.1364/OE.27.008529.

Authors

E Talamas Simola, A De Iacovo, J Frigerio, A Ballabio, A Fabbri, G Isella, L Colace

PMID: 31052668
DOI: 10.1364/OE.27.008529

Abstract

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 (<-30dB), a wide dynamic range (>120dB) and, thanks to their low voltage operation, maximum specific detectivities of 7·10¹¹cmHz^1/2/W and 2·10¹⁰cmHz^1/2/W in the VIS and NIR, respectively.