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Submicron Size Schottky Junctions on As-Grown Monolayer Epitaxial Graphene on Ge(100): A Low-Invasive Scanned-Probe-Based Study
journal contribution
posted on 2019-09-11, 18:33 authored by Marialilia Pea, Monica De Seta, Luciana Di Gaspare, Luca Persichetti, Andrea Maria Scaparro, Vaidotas Miseikis, Camilla Coletti, Andrea NotargiacomoWe
report on the investigation of the Schottky barrier (SB) formed
at the junction between a metal-free graphene monolayer and Ge semiconductor
substrate in the as-grown epitaxial graphene/Ge(100) system.
In order to preserve the heterojunction properties, we defined submicron
size graphene/Ge junctions using the scanning probe microscopy lithography
in the local oxidation configuration, a low-invasive processing approach
capable of inducing spatially controlled electrical separations among
tiny graphene regions. Characteristic junction parameters were estimated
from I–V curves obtained
using conductive-atomic force microscopy. The current–voltage
characteristics showed a p-type Schottky contact behavior, ascribed
to the n-type to p-type conversion of the entire Ge substrate due
to the formation of a large density of acceptor defects during the
graphene growth process. We estimated, for the first time, the energy
barrier height in the as-grown graphene/Ge Schottky junction (φB ≈ 0.45 eV) indicating an n-type doping of the graphene
layer with a Fermi level ≈ 0.15 eV above the Dirac point. The
SB devices showed ideality factor values around 1.5 pointing to the
high quality of the heterojunctions.
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p-type Schottky contact behavioroxidation configurationgraphene regionsgraphene layerlow-invasive processing approachmetal-free graphene monolayerCharacteristic junction parametersgraphene growth processscanning probe microscopy lithographyLow-Invasive Scanned-Probe-Based Studyacceptor defectsenergy barrier heightp-type conversionheterojunction propertiesSubmicron Size Schottky JunctionsAs-Grown Monolayer Epitaxial GrapheneSchottky barriern-type dopingideality factor valuesconductive-atomic force microscopyDirac pointGe semiconductor substrate inSB devicesGe substrate
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