Abstract-An in situ rewritable electrically-erasable photo-memory device for terahertz waves

Luyao Xiong, Bin Liu, Dandan Liu, Longfeng Lv, Yanbing Hou, Jingling Shen, Bo Zhang

https://pubs.rsc.org/en/Content/ArticleLanding/2020/NR/C9NR08826A#!divAbstract

A terahertz read-only in situ electrically-erasable rewritable photo-memory device based on a perovskite:Ag (perovskite with Ag nanoparticles added)/SnO2/PEDOT:PSS hetero-junction structure is reported. Under low optical excitation, considerable terahertz amplitude modulation in a perovskite:Ag/PEDOT:PSS hybrid structure was achieved. When a SnO2 nanoparticle film was inserted between the perovskite and PEDOT:PSS layer, the attenuation of the terahertz signal was weaker than that of the perovskite:Ag/PEDOT:PSS hybrid structure; however, the SnO2 nanoparticle film considerably prolonged the recovery time of the modulated terahertz wave in air after photo-excitation was stopped. In addition, when bias voltages were applied to the perovskite:Ag/PEDOT:PSS and perovskite:Ag/SnO2/PEDOT:PSS hybrid structures, respectively, the terahertz signals recovered rapidly for both structures. Consequently, the photo-memory functionality was achieved based on a perovskite:Ag/SnO2/PEDOT:PSS hybrid structure with an in situ method for erasing stored information.

Abstract-Terahertz read-only multi-order nonvolatile rewritable photo-memory based on indium oxide nanoparticles

Applied Physics Letters

Hongyu Ji, Wei Wang, Luyao Xiong, Dandan Liu, Longfeng Lv, Bo Zhang, Jingling Shen,

(a) Schematic of the terahertz time-domain spectroscopy (THz-TDS) system. (b) Absorption spectrum and scanning electron microscopy (SEM) image of the indium oxide sample

https://aip.scitation.org/doi/abs/10.1063/1.5051029

We investigate terahertz (THz) read-only multi-order nonvolatile rewritable photo-memory based on indium oxide (In2O3) nanoparticles. Optical excitation of an In2O3/quartz sample increases its conductivity, which attenuates its THz transmission. When the optical excitation is terminated, the modulated THz transmission can recover back to its original value in air. However, the THz transmission shows no obvious change over a long-term when In2O3/quartz is encapsulated in an inert gas (nitrogen). Multi-order nonvolatile digital information storage is obtained at different light intensities, and the photo-memory can be rewritten after thermal annealing. Different THz transmissions are used as coded signal units, which are programmed to store information. These results show that THz read-only multi-level nonvolatile rewritable photo-memory can be realized.

Abstract-Ultraviolet light-induced terahertz modulation based on indium oxide thin film

Hongyu Ji, Bo Zhang, Wei Wang, Guocui Wang, Longfeng Lv, and Jingling Shen

https://www.osapublishing.org/abstract.cfm?uri=isuptw-2018-WI19&origin=search

An active ultraviolet light-induced terahertz modulation based on indium oxide thin film was investigated in which exhibit a large absorption modulation of ~50% when illuminated by a low intensity UV laser (11 mW/cm2). The interaction between indium oxide and the metamaterial structure was investigated due to the large enhancement of photo carriers in UV-induced in indium oxide film. We can realize the absorption peak shifts of 37 GHz by changing the UV excited light intensity.

© 2018 The Author(s)

Abstract-Ultraviolet light-induced terahertz modulation of an indium oxide film

Hongyu Ji, Bo Zhang, Wei Wang, Longfeng Lv, and Jingling Shen

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-26-6-7204

Active ultraviolet light-induced terahertz modulation of an indium oxide film is investigated. A large absorption modulation of ~66% is achieved upon illumination with a low intensity UV laser (11 mW/cm2). The interaction between indium oxide and a flexible metamaterial structure is investigated owing to the large UV-induced enhancement of photo carriers observed in an indium oxide film. We are able to realize absorption peak shifts of 37 GHz by changing the UV excitation light intensity. We also propose a multi-frequency switch by building a circular metallic split ring resonator whose gaps are filled with silicon, germanium, and indium oxide. In future, a photo-excited tunable multi-frequency metamaterial switch can be realized by irradiating the structure with multi-wavelength laser beam.

© 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Abstract-Monolayer graphene based organic optical terahertz modulator

Guocui Wang, Bo Zhang, Hongyu Ji,   Xin Liu, Ting He, Longfeng Lv, Yanbing Hou,  Jingling Shen,

http://aip.scitation.org/doi/full/10.1063/1.4973816

We investigate a high-efficiency broadband terahertz wave modulator with structures made from the conjugated polymer [2-methoxy-5-(2′-ethylhexyloxy)-1, 4-phenylennevinylene], graphene, and Si, irradiated with an external excitation laser. We demonstrate a strategy that can alleviate the tradeoff between the requirements of modulation depth and modulation speed in polymer/silicon terahertz wave modulators. Using terahertz time-domain and continuous-wave systems, we measured both the terahertz transmission modulation properties and the time responses of the modulator structures. The conjugated polymer/graphene/silicon structure achieved a high modulation factor of 93% for transmission as well as improved the modulation speed of the devices based on polymer/silicon. The high modulation efficiency of the polymer/graphene/silicon structure was induced by the enhancement in carrier density and the extremely high carrier mobility of graphene, respectively.

Abstract-Conjugated polymer based active electric-controlled terahertz device

Liang Zhong1, Bo Zhang1,a), Ting He1, Longfeng Lv2, Yanbing Hou2 andJingling Shen1,a





http://scitation.aip.org/content/aip/journal/apl/108/10/10.1063/1.4943648
http://scitation.aip.org/content/aip/journal/apl/108/10/10.1063/1.4943648







A modulation of terahertz response in a highly efficient, electric-controlled conjugated polymer-silicon hybrid device with low photo-excitation was investigated. The polymer-silicon forms a hybrid structure,where the active depletion region modifies the semiconductor conductivity in real time by applying an external bias voltage. The THz transmission was efficiently modulated by effective controlling. In a THz-TDS system, the modulation depth reached nearly 100% when the applied voltage was 3.8 V at an external laser intensity of 0.3 W/cm2. The saturation voltage decreased with increasing photo-excited intensity. In a THz-CW system, a significant decline in THz transmission was also observed with increasing applied bias voltage. This reduction in THz transmission is induced by the enhancement of carrier densit

Abstract-Active terahertz device based on optically controlled organometal halide perovskite

Bo Zhang^1,a), Longfeng Lv², Ting He¹, Tianji Chen¹, Mengdi Zang¹, Liang Zhong¹, Xinke Wang¹, Jingling Shen^1,a) and Yanbing Hou²
http://scitation.aip.org/content/aip/journal/apl/107/9/10.1063/1.4930164
a) Authors to whom correspondence should be addressed. Electronic addresses: bzhang@cnu.edu.cnand sjl-phy@cnu.edu.cn.
Appl. Phys. Lett. 107, 093301 (2015); http://dx.doi.org/10.1063/1.4930164

An active all-optical high-efficiency broadband terahertz device based on an organometal halideperovskite (CH3NH3PbI3, MAPbI3)/inorganic (Si) structure is investigated. Spectrally broadband modulation of the THz transmission is obtained in the frequency range from 0.2 to 2.6 THz, and a modulation depth of nearly 100% can be achieved with a low-level photoexcitation power (∼0.4 W/cm²). Both THz transmission and reflection were suppressed in the MAPbI3/Sistructure by an external continuous-wave (CW) laser. Enhancement of the charge carrier density at the MAPbI3/Si interface is crucial for photo-induced absorption. The results show that the proposed high-efficiency broadband optically controlled terahertz device based on the MAPbI3/Si structure has been realized.