Issue 24, 2012

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

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.

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

Supplementary files

Article information

Article type
Paper
Submitted
31 Aug 2012
Accepted
26 Oct 2012
First published
29 Oct 2012

Nanoscale, 2012,4, 7842-7846

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

A. Aparecido-Ferreira, H. Miyazaki, S. Li, K. Komatsu, S. Nakaharai and K. Tsukagoshi, Nanoscale, 2012, 4, 7842 DOI: 10.1039/C2NR32526H

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