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Title: Optical Determination of Gate--Tunable Bandgap in Bilayer Graphene

Abstract

The electronic bandgap is an intrinsic property of semiconductors and insulators that largely determines their transport and optical properties. As such, it has a central role in modern device physics and technology and governs the operation of semiconductor devices such as p-n junctions, transistors, photodiodes and lasers. A tunable bandgap would be highly desirable because it would allow great flexibility in design and optimization of such devices, in particular if it could be tuned by applying a variable external electric field. However, in conventional materials, the bandgap is fixed by their crystalline structure, preventing such bandgap control. Here we demonstrate the realization of a widely tunable electronic bandgap in electrically gated bilayer graphene. Using a dual-gate bilayer graphene field-effect transistor (FET) and infrared microspectroscopy, we demonstrate a gate-controlled, continuously tunable bandgap of up to 250 meV. Our technique avoids uncontrolled chemical doping and provides direct evidence of a widely tunable bandgap -- spanning a spectral range from zero to mid-infrared -- that has eluded previous attempts. Combined with the remarkable electrical transport properties of such systems, this electrostatic bandgap control suggests novel nanoelectronic and nanophotonic device applications based on graphene.

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
Advanced Light Source Division; Earth Sciences Division
OSTI Identifier:
974550
Report Number(s):
LBNL-2786E
TRN: US201007%%797
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Journal Article
Journal Name:
Nature
Additional Journal Information:
Journal Name: Nature
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; DESIGN; ELECTRIC FIELDS; ELECTROSTATICS; FIELD EFFECT TRANSISTORS; FLEXIBILITY; LASERS; OPTICAL PROPERTIES; OPTIMIZATION; PHOTODIODES; PHYSICS; P-N JUNCTIONS; SEMICONDUCTOR DEVICES; TRANSISTORS; TRANSPORT; electrically gated bandgap bilayer graphene dual-gate gate-controlled, transport, nanophotonic

Citation Formats

Zhang, Yuanbo, Tang, Tsung-Ta, Girit, Caglar, Hao, Zhao, Martin, Michael C, Zettl, Alex, Crommie, Michael F, Shen, Y Ron, and Wang, Feng. Optical Determination of Gate--Tunable Bandgap in Bilayer Graphene. United States: N. p., 2009. Web. doi:10.1038/nature08105.
Zhang, Yuanbo, Tang, Tsung-Ta, Girit, Caglar, Hao, Zhao, Martin, Michael C, Zettl, Alex, Crommie, Michael F, Shen, Y Ron, & Wang, Feng. Optical Determination of Gate--Tunable Bandgap in Bilayer Graphene. United States. doi:10.1038/nature08105.
Zhang, Yuanbo, Tang, Tsung-Ta, Girit, Caglar, Hao, Zhao, Martin, Michael C, Zettl, Alex, Crommie, Michael F, Shen, Y Ron, and Wang, Feng. Tue . "Optical Determination of Gate--Tunable Bandgap in Bilayer Graphene". United States. doi:10.1038/nature08105. https://www.osti.gov/servlets/purl/974550.
@article{osti_974550,
title = {Optical Determination of Gate--Tunable Bandgap in Bilayer Graphene},
author = {Zhang, Yuanbo and Tang, Tsung-Ta and Girit, Caglar and Hao, Zhao and Martin, Michael C and Zettl, Alex and Crommie, Michael F and Shen, Y Ron and Wang, Feng},
abstractNote = {The electronic bandgap is an intrinsic property of semiconductors and insulators that largely determines their transport and optical properties. As such, it has a central role in modern device physics and technology and governs the operation of semiconductor devices such as p-n junctions, transistors, photodiodes and lasers. A tunable bandgap would be highly desirable because it would allow great flexibility in design and optimization of such devices, in particular if it could be tuned by applying a variable external electric field. However, in conventional materials, the bandgap is fixed by their crystalline structure, preventing such bandgap control. Here we demonstrate the realization of a widely tunable electronic bandgap in electrically gated bilayer graphene. Using a dual-gate bilayer graphene field-effect transistor (FET) and infrared microspectroscopy, we demonstrate a gate-controlled, continuously tunable bandgap of up to 250 meV. Our technique avoids uncontrolled chemical doping and provides direct evidence of a widely tunable bandgap -- spanning a spectral range from zero to mid-infrared -- that has eluded previous attempts. Combined with the remarkable electrical transport properties of such systems, this electrostatic bandgap control suggests novel nanoelectronic and nanophotonic device applications based on graphene.},
doi = {10.1038/nature08105},
journal = {Nature},
number = ,
volume = ,
place = {United States},
year = {2009},
month = {8}
}