We realize two graphene/Si devices with the same structure but on different Si type and characterize their current-voltage properties. We observe that the gr/n-Si junction has a higher Schottky barrier and rectification factor than the gr/p-Si junction. The low Schottky barrier of the gr/p-Si junction is explained by the p-doping of graphene, induced by polymethylmethacrylate residues and chemicals used for the transfer process, which align the graphene Fermi level to the Si valence band. Under illumination, both devices show a reverse current greater than the forward one. This phenomenon is attributed to the metal-oxidesemiconductor capacitor connected in parallel with the gr/Si Schottky junction. Although both junctions possess a high responsivity, the gr/p-Si junction shows a high dark current that hampers its use as photo detector.

Effect of silicon doping on graphene/silicon Schottky photodiodes

Luongo, Giuseppe;Grillo, Alessandro;Urban, Francesca;Giubileo, Filippo;Di Bartolomeo, Antonio
2020

Abstract

We realize two graphene/Si devices with the same structure but on different Si type and characterize their current-voltage properties. We observe that the gr/n-Si junction has a higher Schottky barrier and rectification factor than the gr/p-Si junction. The low Schottky barrier of the gr/p-Si junction is explained by the p-doping of graphene, induced by polymethylmethacrylate residues and chemicals used for the transfer process, which align the graphene Fermi level to the Si valence band. Under illumination, both devices show a reverse current greater than the forward one. This phenomenon is attributed to the metal-oxidesemiconductor capacitor connected in parallel with the gr/Si Schottky junction. Although both junctions possess a high responsivity, the gr/p-Si junction shows a high dark current that hampers its use as photo detector.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11386/4734165
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