Enhanced current-rectification in bilayer graphene with an electrically tuned sloped bandgap

Alex Aparecido-Ferreira, Hisao Miyazaki, Song Lin Li, Katsuyoshi Komatsu, Shu Nakaharai, Kazuhito Tsukagoshi

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)

Abstract

We propose a novel sloped dielectric geometry in graphene as a band engineering method for widening the depletion region and increasing the electrical rectification effect in graphene pn junctions. Enhanced current-rectification was achieved in a bilayer graphene with a sloped dielectric top gate and a normal back gate. A bias was applied to the top gate to induce a spatially modulated and sloped band configuration, while a back-gate bias was applied to open a bandgap. The sloped band can be tuned to separate n- and p-type regions in the bilayer graphene, depending on a suitable choice of gate voltage. The effective depletion region between the n- and p-type regions can be spatially enlarged due to the proposed top-gate structure. As a result, a strong non-linear electric current was observed during drain bias sweeping, demonstrating the expected rectification behavior with an on/off ratio higher than all previously reported values for graphene pn junctions. The observed rectification was modified to a linear current-voltage relationship by adjusting the biases of both gates to form an nn- or pp-type junction configuration. These results demonstrate that an external voltage can control the current flow in atomic film diodes.

Original languageEnglish
Pages (from-to)7842-7846
Number of pages5
JournalNanoscale
Volume4
Issue number24
DOIs
Publication statusPublished - 2012 Jan 1
Externally publishedYes

ASJC Scopus subject areas

  • Materials Science(all)

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