Low Voltage Graphene-Based Amplitude Modulator for High Efficiency Terahertz Modulation.

Qianying Zheng,Liangping Xia,Linlong Tang,Hongliang Cui,Chunlei Du

doi:10.3390/nano10030585

Abstract

In this paper, a high-efficiency terahertz amplitude modulation device based on a field-effect transistor has been proposed. The polarization insensitive modulator is designed to achieve a maximum experimental modulation depth of about 53% within 5 V of gate voltages using monolayer graphene. Moreover, the manufacturing processes are inexpensive. Two methods are adopted to improve modulation performance. For one thing, the metal metamaterial designed can effectively enhance the electromagnetic field near single-layer graphene and therefore greatly promote the graphene’s modulation ability in terahertz. For another, polyethylene oxide-based electrolytes (PEO:LiClO4) acts as a high-capacity donor, which makes it possible to dope single-layer graphene at a relatively low voltage.

Highlights

The electromagnetic spectrum from 0.1 to 10 terahertz (THz) is called the THz region
According to the previous study, the electromagnetic fields surrounding graphene could be extremely magnified, over a hundred times, by integrating graphene with metamaterial [16]. Another deficiency is that the drawing-voltage of THz graphene modulators is generally as high as several tens of volts [13,17]. Given all these dynamic devices are controlled by manipulating the carrier concentration of graphene, enhancing doping efficiency will be a crucial point to realNiazneomdaeteeripalst2u02n0a, 1b0l,ex FeOleRmPEeEnRtRsEwVIiEtWh low voltage
In order to analyze the device using a theoretical model, we need to figure out the relationship between the applied gate voltage and the corresponding Fermi level of SLG graphene

Summary

Introduction

The electromagnetic spectrum from 0.1 to 10 terahertz (THz) is called the THz region. According to the previous study, the electromagnetic fields surrounding graphene could be extremely magnified, over a hundred times, by integrating graphene with metamaterial [16] Another deficiency is that the drawing-voltage of THz graphene modulators is generally as high as several tens of volts [13,17]. Given all these dynamic devices are controlled by manipulating the carrier concentration of graphene, enhancing doping efficiency will be a crucial point to realNiazneomdaeteeripalst2u02n0a, 1b0l,ex FeOleRmPEeEnRtRsEwVIiEtWh low voltage. Ionccduertrainilg, tahte−i3n.5crVea, stehde mraatexiomf uMmDMgDradisu5a5ll%y aslto6wVs.dTohwe nre, lwatiitohntshheipapbeptlwieedenvoglatategevsoslthaigfteinagndawMaDy fisronmonth-leinDeairra.cInpodientta. il, the increased rate of MD gradually slows down, with the applied voltages shifting away from the Dirac point

Discussion

Solid Electrolyte Model

Findings

Conclusions