Graphene-silicon-on-insulator (GSOI) Schottky diode photodetectors

Graphene-silicon (GS) Schottky junctions have been demonstrated as an efficient architecture for photodetection. However, the response speed of such devices for free space light detection has so far been limited to 10s-100s of kHz for wavelength λ >500 nm. Here, we demonstrate GS Schottky junctio...

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Bibliographic Details
Published in:Nanoscale 2018-10, Vol.1 (4), p.18926-18935
Main Authors: Selvi, Hakan, Hill, Ernie W, Parkinson, Patrick, Echtermeyer, Tim J
Format: Article
Language:English
Subjects:
Diffusion rate
Electrical junctions
Graphene
Optical components
Photometers
Schottky diodes
Silicon
Silicon substrates
Thickness
Topography
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Summary:Graphene-silicon (GS) Schottky junctions have been demonstrated as an efficient architecture for photodetection. However, the response speed of such devices for free space light detection has so far been limited to 10s-100s of kHz for wavelength λ >500 nm. Here, we demonstrate GS Schottky junction photodetectors fabricated on a silicon-on-insulator substrate (SOI) with response speeds approaching 1 GHz, attributed to the reduction of the photo-active silicon layer thickness to 10 μm and with it a suppression of speed-limiting diffusion currents. Graphene-silicon-on-insulator photodetectors (GSOI-PDs) exhibit a negligible influence of wavelength on response speed and only a modest compromise in responsivities compared to GS junctions fabricated on bulk silicon. Noise-equivalent-power (NEP) and specific detectivity ( D *) of GSOI photodetectors are 14.5 pW and 7.83 × 10 10 cm Hz 1/2 W −1 , respectively, in ambient conditions. We further demonstrate that combining GSOI-PDs with micro-optical elements formed by modifying the surface topography enables engineering of the spectral and angular response. Graphene-silicon-on-insulator (GSOI) photodetectors for high-speed free space light detection.
ISSN:2040-3364
2040-3372
DOI:10.1039/c8nr05285a