High-Performance All-Optical Terahertz Modulator Based on Graphene/TiO2/Si Trilayer Heterojunctions

Miaoqing Wei; Dainan Zhang; Yuanpeng Li; Lei Zhang; Lichuan Jin; Tianlong Wen; Feiming Bai; Huaiwu Zhang

doi:10.1186/s11671-019-2996-9

Nanoscale Research Letters (May 2019)

High-Performance All-Optical Terahertz Modulator Based on Graphene/TiO2/Si Trilayer Heterojunctions

Miaoqing Wei,
Dainan Zhang,
Yuanpeng Li,
Lei Zhang,
Lichuan Jin,
Tianlong Wen,
Feiming Bai,
Huaiwu Zhang

Affiliations

Miaoqing Wei: State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China
Dainan Zhang: State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China
Yuanpeng Li: State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China
Lei Zhang: State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China
Lichuan Jin: State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China
Tianlong Wen: State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China
Feiming Bai: State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China
Huaiwu Zhang: State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China

DOI: https://doi.org/10.1186/s11671-019-2996-9
Journal volume & issue: Vol. 14, no. 1
pp. 1 – 6

Abstract

Read online

Abstract In this paper, we demonstrate a trilayer hybrid terahertz (THz) modulator made by combining a p-type silicon (p-Si) substrate, TiO2 interlayer, and single-layer graphene. The interface between Si and TiO2 introduced a built-in electric field, which drove the photoelectrons from Si to TiO2, and then the electrons injected into the graphene layer, causing the Fermi level of graphene to shift into a higher conduction band. The conductivity of graphene would increase, resulting in the decrease of transmitted terahertz wave. And the terahertz transmission modulation was realized. We observed a broadband modulation of the terahertz transmission in the frequency range from 0.3 to 1.7 THz and a large modulation depth of 88% with proper optical excitation. The results show that the graphene/TiO2/p-Si hybrid nanostructures exhibit great potential for terahertz broadband applications, such as terahertz imaging and communication.

Published in Nanoscale Research Letters

ISSN: 1931-7573 (Print); 1556-276X (Online)
Publisher: SpringerOpen
Country of publisher: United Kingdom
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Materials of engineering and construction. Mechanics of materials
Website: https://www.springer.com/journal/11671

About the journal

Abstract

Keywords