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-Active bidirectional electrically-controlled terahertz device based on dimethyl sulfoxide-doped PEDOT:PSS

Wei Wang, Hongyu Ji, Dandan Liu, Luyao Xiong, Yanbing Hou, Bo Zhang, and Jingling She

Fig. 3 (a) Setup for measurement of the signals of the modulated THz beam based on THz-TDS. (b) Measured signals of the modulated THz beam when the bias is positive (red line) and negative (blue line) for the MPSP sample.

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-26-20-25849

A high-efficiency active bidirectional electrically-controlled terahertz device based on DMSO-doped PEDOT:PSS with low-power photoexcitation is investigated. Under low-power optical excitation of 30 mW (0.5 W/cm2) and under bias voltages ranging from −0.6 V to 0.5 V, spectrally broadband modulation of THz transmission over a range from −54% to 60% is obtained over the frequency range from 0.2 to 2.6 THz in a MEH-PPV/PEDOT:PSS:DMSO/Si/PEDOT:PSS:DMSO hybrid structure. By considering the combined carrier density characteristics of the proposed device, it is found that the large-scale amplitude modulation can be ascribed to the electrically-controlled carrier density in the silicon layer with the assistance of the p-n junction that consists of the DMSO-doped PEDOT:PSS and silicon. Bidirectional modulation has a larger modulation range and is easier to use in communications applications when compared with unidirectional modulation. These results show great potential for application to the design of active broadband terahertz devices.

© 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-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.