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Published on: October 23, 2018
p-Type Schottky Contacts for Graphene Adjustable-Barrier Phototransistors
Carsten Strobel1, Carlos Alvarado Chavarin2, Martin Knaut1
1Institute of Semiconductors and Microsystems, Chair of Nanoelectronics, Technische Universität Dresden, Nöthnitzer Straße 64, 01187 Dresden, Germany.
Abstract:
The graphene adjustable-barriers phototransistor is an attractive novel device for potential high speed and high responsivity dual-band photodetection. In this device, graphene is embedded between the semiconductors silicon and germanium. Both n-type and p-type Schottky contacts between graphene and the semiconductors are required for this device. While n-type Schottky contacts are widely investigated, reports about p-type Schottky contacts between graphene and the two involved semiconductors are scarce. In this study, we demonstrate a p-type Schottky contact between graphene and p-germanium. A clear rectification with on-off ratios of close to 103 (±5 V) and a distinct photoresponse at telecommunication wavelengths in the infrared are achieved. Further, p-type silicon is transferred to or deposited on graphene, and we also observe rectification and photoresponse in the visible range for some of these p-type Schottky junctions. These results are an important step toward the realization of functional graphene adjustable-barrier phototransistors.
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