Wu Yang
Degree: PhD
Position: Grad Students
Affiliation: Faculty of Engineering
Research Type: Experiment
Email: a0092769@nus.edu.sg
CA2DM Publications:
2020 |
Liang, Shiheng; Shi, Shuyuan; Hsu, Chuang-Han; Cai, Kaiming; Wang, Yi; He, Pan; Wu, Yang; Pereira, Vitor M; Yang, Hyunsoo Spin-Orbit Torque Magnetization Switching in MoTe2/Permalloy Heterostructures Journal Article ADVANCED MATERIALS, 32 (37), 2020, ISSN: 0935-9648. @article{ISI:000554472200001, title = {Spin-Orbit Torque Magnetization Switching in MoTe_{2}/Permalloy Heterostructures}, author = {Shiheng Liang and Shuyuan Shi and Chuang-Han Hsu and Kaiming Cai and Yi Wang and Pan He and Yang Wu and Vitor M Pereira and Hyunsoo Yang}, doi = {10.1002/adma.202002799}, times_cited = {8}, issn = {0935-9648}, year = {2020}, date = {2020-08-02}, journal = {ADVANCED MATERIALS}, volume = {32}, number = {37}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {The ability to switch magnetic elements by spin-orbit-induced torques has recently attracted much attention for a path toward high-performance, nonvolatile memories with low power consumption. Realizing efficient spin-orbit-based switching requires the harnessing of both new materials and novel physics to obtain high charge-to-spin conversion efficiencies, thus making the choice of spin source crucial. Here, the observation of spin-orbit torque switching in bilayers consisting of a semimetallic film of 1T '-MoTe(2)adjacent to permalloy is reported. Deterministic switching is achieved without external magnetic fields at room temperature, and the switching occurs with currents one order of magnitude smaller than those typical in devices using the best-performing heavy metals. The thickness-dependence can be understood if the interfacial spin-orbit contribution is considered in addition to the bulk spin Hall effect. Further threefold reduction in the switching current is demonstrated with resort to dumbbell-shaped magnetic elements. These findings foretell exciting prospects of using MoTe(2)for low-power semimetal-material-based spin devices.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The ability to switch magnetic elements by spin-orbit-induced torques has recently attracted much attention for a path toward high-performance, nonvolatile memories with low power consumption. Realizing efficient spin-orbit-based switching requires the harnessing of both new materials and novel physics to obtain high charge-to-spin conversion efficiencies, thus making the choice of spin source crucial. Here, the observation of spin-orbit torque switching in bilayers consisting of a semimetallic film of 1T '-MoTe(2)adjacent to permalloy is reported. Deterministic switching is achieved without external magnetic fields at room temperature, and the switching occurs with currents one order of magnitude smaller than those typical in devices using the best-performing heavy metals. The thickness-dependence can be understood if the interfacial spin-orbit contribution is considered in addition to the bulk spin Hall effect. Further threefold reduction in the switching current is demonstrated with resort to dumbbell-shaped magnetic elements. These findings foretell exciting prospects of using MoTe(2)for low-power semimetal-material-based spin devices. |
2018 |
Wang, Qisheng; Li, Jie; Besbas, Jean; Hsu, Chuang-Han; Cai, Kaiming; Yang, Li; Cheng, Shuai; Wu, Yang; Zhang, Wenfeng; Wang, Kaiyou; Chang, Tay-Rong; Lin, Hsin; Chang, Haixin; Yang, Hyunsoo Room-Temperature Nanoseconds Spin Relaxation in WTe2 and MoTe2 Thin Films Journal Article ADVANCED SCIENCE, 5 (6), 2018, ISSN: 2198-3844. @article{ISI:000435765900023, title = {Room-Temperature Nanoseconds Spin Relaxation in WTe_{2} and MoTe_{2} Thin Films}, author = {Qisheng Wang and Jie Li and Jean Besbas and Chuang-Han Hsu and Kaiming Cai and Li Yang and Shuai Cheng and Yang Wu and Wenfeng Zhang and Kaiyou Wang and Tay-Rong Chang and Hsin Lin and Haixin Chang and Hyunsoo Yang}, doi = {10.1002/advs.201700912}, times_cited = {0}, issn = {2198-3844}, year = {2018}, date = {2018-06-01}, journal = {ADVANCED SCIENCE}, volume = {5}, number = {6}, publisher = {WILEY}, address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA}, abstract = {The Weyl semimetal WTe2 and MoTe2 show great potential in generating large spin currents since they possess topologically protected spin-polarized states and can carry a very large current density. In addition, the intrinsic non-centrosymmetry of WTe2 and MoTe2 endows with a unique property of crystal symmetry-controlled spin-orbit torques. An important question to be answered for developing spintronic devices is how spins relax in WTe2 and MoTe2. Here, a room-temperature spin relaxation time of 1.2ns (0.4ns) in WTe2 (MoTe2) thin film using the time-resolved Kerr rotation (TRKR) is reported. Based on ab initio calculation, a mechanism of long-lived spin polarization resulting from a large spin splitting around the bottom of the conduction band, low electron-hole recombination rate, and suppression of backscattering required by time-reversal and lattice symmetry operation is identified. In addition, it is found that the spin polarization is firmly pinned along the strong internal out-of-plane magnetic field induced by large spin splitting. This work provides an insight into the physical origin of long-lived spin polarization in Weyl semimetals, which could be useful to manipulate spins for a long time at room temperature.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The Weyl semimetal WTe2 and MoTe2 show great potential in generating large spin currents since they possess topologically protected spin-polarized states and can carry a very large current density. In addition, the intrinsic non-centrosymmetry of WTe2 and MoTe2 endows with a unique property of crystal symmetry-controlled spin-orbit torques. An important question to be answered for developing spintronic devices is how spins relax in WTe2 and MoTe2. Here, a room-temperature spin relaxation time of 1.2ns (0.4ns) in WTe2 (MoTe2) thin film using the time-resolved Kerr rotation (TRKR) is reported. Based on ab initio calculation, a mechanism of long-lived spin polarization resulting from a large spin splitting around the bottom of the conduction band, low electron-hole recombination rate, and suppression of backscattering required by time-reversal and lattice symmetry operation is identified. In addition, it is found that the spin polarization is firmly pinned along the strong internal out-of-plane magnetic field induced by large spin splitting. This work provides an insight into the physical origin of long-lived spin polarization in Weyl semimetals, which could be useful to manipulate spins for a long time at room temperature. |
2017 |
Wang, Yi; Zhu, Dapeng; Wu, Yang; Yang, Yumeng; Yu, Jiawei; Ramaswamy, Rajagopalan; Mishra, Rahul; Shi, Shuyuan; Elyasi, Mehrdad; Teo, Kie-Leong; Wu, Yihong; Yang, Hyunsoo Room temperature magnetization switching in topological insulator-ferromagnet heterostructures by spin-orbit torques Journal Article NATURE COMMUNICATIONS, 8 , 2017, ISSN: 2041-1723. @article{ISI:000414662500005, title = {Room temperature magnetization switching in topological insulator-ferromagnet heterostructures by spin-orbit torques}, author = {Yi Wang and Dapeng Zhu and Yang Wu and Yumeng Yang and Jiawei Yu and Rajagopalan Ramaswamy and Rahul Mishra and Shuyuan Shi and Mehrdad Elyasi and Kie-Leong Teo and Yihong Wu and Hyunsoo Yang}, doi = {10.1038/s41467-017-01583-4}, times_cited = {0}, issn = {2041-1723}, year = {2017}, date = {2017-11-08}, journal = {NATURE COMMUNICATIONS}, volume = {8}, publisher = {NATURE PUBLISHING GROUP}, address = {MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND}, abstract = {Topological insulators with spin-momentum-locked topological surface states are expected to exhibit a giant spin-orbit torque in the topological insulator/ferromagnet systems. To date, the topological insulator spin-orbit torque-driven magnetization switching is solely reported in a Cr-doped topological insulator at 1.9 K. Here we directly show giant spin-orbit torque-driven magnetization switching in a Bi2Se3/NiFe heterostructure at room temperature captured using a magneto-optic Kerr effect microscope. We identify a large charge-to-spin conversion efficiency of similar to 1-1.75 in the thin Bi2Se3 films, where the topological surface states are dominant. In addition, we find the current density required for the magnetization switching is extremely low, similar to 6 x 10(5) A cm(-2), which is one to two orders of magnitude smaller than that with heavy metals. Our demonstration of room temperature magnetization switching of a conventional 3d ferromagnet using Bi2Se3 may lead to potential innovations in topological insulator-based spintronic applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Topological insulators with spin-momentum-locked topological surface states are expected to exhibit a giant spin-orbit torque in the topological insulator/ferromagnet systems. To date, the topological insulator spin-orbit torque-driven magnetization switching is solely reported in a Cr-doped topological insulator at 1.9 K. Here we directly show giant spin-orbit torque-driven magnetization switching in a Bi2Se3/NiFe heterostructure at room temperature captured using a magneto-optic Kerr effect microscope. We identify a large charge-to-spin conversion efficiency of similar to 1-1.75 in the thin Bi2Se3 films, where the topological surface states are dominant. In addition, we find the current density required for the magnetization switching is extremely low, similar to 6 x 10(5) A cm(-2), which is one to two orders of magnitude smaller than that with heavy metals. Our demonstration of room temperature magnetization switching of a conventional 3d ferromagnet using Bi2Se3 may lead to potential innovations in topological insulator-based spintronic applications. |
Wu, Yang; Qiu, Xuepeng; Liu, Hongwei; Liu, Jingbo; Chen, Yuanfu; Ke, Lin; Yang, Hyunsoo Tunable terahertz reflection of graphene via ionic liquid gating Journal Article NANOTECHNOLOGY, 28 (9), 2017, ISSN: 0957-4484. @article{ISI:000395071700001, title = {Tunable terahertz reflection of graphene via ionic liquid gating}, author = {Yang Wu and Xuepeng Qiu and Hongwei Liu and Jingbo Liu and Yuanfu Chen and Lin Ke and Hyunsoo Yang}, doi = {10.1088/1361-6528/aa57ad}, times_cited = {0}, issn = {0957-4484}, year = {2017}, date = {2017-03-03}, journal = {NANOTECHNOLOGY}, volume = {28}, number = {9}, publisher = {IOP PUBLISHING LTD}, address = {TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND}, abstract = {We report a highly efficient tunable THz reflector in graphene. By applying a small gate voltage (up to +/- 3V), the reflectance of graphene is modulated from a minimum of 0.79% to a maximum of 33.4% using graphene/ionic liquid structures at room temperature, and the reflection tuning is uniform within a wide spectral range (0.1-1.5 THz). Our observation is explained by the Drude model, which describes the THz wave-induced intraband transition in graphene. This tunable reflectance of graphene may contribute to broadband THz mirrors, deformable THz mirrors, variable THz beam splitters and other optical components.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We report a highly efficient tunable THz reflector in graphene. By applying a small gate voltage (up to +/- 3V), the reflectance of graphene is modulated from a minimum of 0.79% to a maximum of 33.4% using graphene/ionic liquid structures at room temperature, and the reflection tuning is uniform within a wide spectral range (0.1-1.5 THz). Our observation is explained by the Drude model, which describes the THz wave-induced intraband transition in graphene. This tunable reflectance of graphene may contribute to broadband THz mirrors, deformable THz mirrors, variable THz beam splitters and other optical components. |
2016 |
Lu, Yao; Song, Jingchao; Yuan, Jian; Zhang, Lei; Wu, Steve Qing Yang; Yu, Wenzhi; Zhao, Meng; Qiu, Cheng-Wei; Teng, Jinghua; Loh, Kian Ping; Zhang, Chao; Bao, Qiaoliang Highly efficient plasmon excitation in graphene-Bi2Te3 heterostructure Journal Article JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS, 33 (9), pp. 1842-1846, 2016, ISSN: 0740-3224. @article{ISI:000385419900008, title = {Highly efficient plasmon excitation in graphene-Bi_{2}Te_{3} heterostructure}, author = {Yao Lu and Jingchao Song and Jian Yuan and Lei Zhang and Steve Qing Yang Wu and Wenzhi Yu and Meng Zhao and Cheng-Wei Qiu and Jinghua Teng and Kian Ping Loh and Chao Zhang and Qiaoliang Bao}, doi = {10.1364/JOSAB.33.001842}, times_cited = {0}, issn = {0740-3224}, year = {2016}, date = {2016-09-01}, journal = {JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS}, volume = {33}, number = {9}, pages = {1842-1846}, publisher = {OPTICAL SOC AMER}, address = {2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA}, abstract = {Graphene plasmons have attracted a lot of attention due to large confinement and small mode volume. However, the graphene-based plasmonic devices are still limited in the practical applications due to relatively small light absorption of graphene and limited light-matter coupling efficiency in general excitation strategy. Here, this work reported a strong plasmonic coupling effect observed in a novel graphene-Bi2Te3 heterostructure on the top of silicon gratings. It is interesting to find that the extinction spectra of the graphene-Bi2Te3 heterostructure has shown three times greater magnitude than that of graphene. This observation is mainly attributed to two factors: first, the coupling efficiency between the graphene and Bi2Te3; second, the higher light absorption in the graphene-Bi2Te3 heterostructure. Moreover, the plasmonic resonance peak of the graphene-Bi2Te3 heterostructure can be easily tuned by changing the grating period just like what happens in the graphene film. In all, this work utilizes the simple silicon grating to couple the light into the graphene-Bi2Te3 heterostructure, and further explores the hybridized Dirac plasmons in the graphene-Bi2Te3 heterostructure. We believe it will stimulate the interest to study the variant plasmonic heterostructure and trigger new terahertz device applications. (C) 2016 Optical Society of America}, keywords = {}, pubstate = {published}, tppubtype = {article} } Graphene plasmons have attracted a lot of attention due to large confinement and small mode volume. However, the graphene-based plasmonic devices are still limited in the practical applications due to relatively small light absorption of graphene and limited light-matter coupling efficiency in general excitation strategy. Here, this work reported a strong plasmonic coupling effect observed in a novel graphene-Bi2Te3 heterostructure on the top of silicon gratings. It is interesting to find that the extinction spectra of the graphene-Bi2Te3 heterostructure has shown three times greater magnitude than that of graphene. This observation is mainly attributed to two factors: first, the coupling efficiency between the graphene and Bi2Te3; second, the higher light absorption in the graphene-Bi2Te3 heterostructure. Moreover, the plasmonic resonance peak of the graphene-Bi2Te3 heterostructure can be easily tuned by changing the grating period just like what happens in the graphene film. In all, this work utilizes the simple silicon grating to couple the light into the graphene-Bi2Te3 heterostructure, and further explores the hybridized Dirac plasmons in the graphene-Bi2Te3 heterostructure. We believe it will stimulate the interest to study the variant plasmonic heterostructure and trigger new terahertz device applications. (C) 2016 Optical Society of America |
Wu, Yang; Niu, Jing; Danesh, Mohammad; Liu, Jingbo; Chen, Yuanfu; Ke, Lin; Qiu, Chengwei; Yang, Hyunsoo Localized surface plasmon resonance in graphene nanomesh with Au nanostructures Journal Article APPLIED PHYSICS LETTERS, 109 (4), 2016, ISSN: 0003-6951. @article{ISI:000381688900006, title = {Localized surface plasmon resonance in graphene nanomesh with Au nanostructures}, author = {Yang Wu and Jing Niu and Mohammad Danesh and Jingbo Liu and Yuanfu Chen and Lin Ke and Chengwei Qiu and Hyunsoo Yang}, doi = {10.1063/1.4959833}, times_cited = {0}, issn = {0003-6951}, year = {2016}, date = {2016-07-25}, journal = {APPLIED PHYSICS LETTERS}, volume = {109}, number = {4}, publisher = {AMER INST PHYSICS}, address = {1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA}, abstract = {A hybrid structure of a graphene nanomesh with the gold nanodisks is studied to enhance the light absorption by the localized surface plasmon resonance. From the reflection spectra of the visible range for graphene nanomesh samples without and with nanodisks, it is found that the absorption of graphene nanomesh structures is greatly enhanced in the presence of gold nanodisks around the resonance wavelength. Simulation results based on the finite-difference time-domain method support the experimental observations. This study demonstrates the potential of constructing graphene based photodetectors with a high light absorption efficiency and wavelength selectivity. Published by AIP Publishing.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A hybrid structure of a graphene nanomesh with the gold nanodisks is studied to enhance the light absorption by the localized surface plasmon resonance. From the reflection spectra of the visible range for graphene nanomesh samples without and with nanodisks, it is found that the absorption of graphene nanomesh structures is greatly enhanced in the presence of gold nanodisks around the resonance wavelength. Simulation results based on the finite-difference time-domain method support the experimental observations. This study demonstrates the potential of constructing graphene based photodetectors with a high light absorption efficiency and wavelength selectivity. Published by AIP Publishing. |
2015 |
Niu, Lin; Liu, Xinfeng; Cong, Chunxiao; Wu, Chunyang; Wu, Di; Chang, Tay Rong; Wang, Hong; Zeng, Qingsheng; Zhou, Jiadong; Wang, Xingli; Fu, Wei; Yu, Peng; Fu, Qundong; Najmaei, Sina; Zhang, Zhuhua; Yakobson, Boris I; Tay, Beng Kang; Zhou, Wu; Jeng, Horng Tay; Lin, Hsin; Sum, Tze Chien; Jin, Chuanhong; He, Haiyong; Yu, Ting; Liu, Zheng Controlled Synthesis of Organic/Inorganic van der Waals Solid for Tunable Light-Matter Interactions Journal Article ADVANCED MATERIALS, 27 (47), pp. 7800-7808, 2015, ISSN: 0935-9648. @article{ISI:000367837900015, title = {Controlled Synthesis of Organic/Inorganic van der Waals Solid for Tunable Light-Matter Interactions}, author = {Lin Niu and Xinfeng Liu and Chunxiao Cong and Chunyang Wu and Di Wu and Tay Rong Chang and Hong Wang and Qingsheng Zeng and Jiadong Zhou and Xingli Wang and Wei Fu and Peng Yu and Qundong Fu and Sina Najmaei and Zhuhua Zhang and Boris I Yakobson and Beng Kang Tay and Wu Zhou and Horng Tay Jeng and Hsin Lin and Tze Chien Sum and Chuanhong Jin and Haiyong He and Ting Yu and Zheng Liu}, doi = {10.1002/adma.201503367}, times_cited = {2}, issn = {0935-9648}, year = {2015}, date = {2015-12-16}, journal = {ADVANCED MATERIALS}, volume = {27}, number = {47}, pages = {7800-7808}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Wu, Yang; La-o-Vorakiat, Chan; Qiu, Xuepeng; Liu, Jingbo; Deorani, Praveen; Banerjee, Karan; Son, Jaesung; Chen, Yuanfu; Chia, Elbert E M; Yang, Hyunsoo Graphene Terahertz Modulators by Ionic Liquid Gating Journal Article ADVANCED MATERIALS, 27 (11), pp. 1874-+, 2015, ISSN: 0935-9648. @article{ISI:000351216500008, title = {Graphene Terahertz Modulators by Ionic Liquid Gating}, author = {Yang Wu and Chan La-o-Vorakiat and Xuepeng Qiu and Jingbo Liu and Praveen Deorani and Karan Banerjee and Jaesung Son and Yuanfu Chen and Elbert E M Chia and Hyunsoo Yang}, doi = {10.1002/adma.201405251}, times_cited = {0}, issn = {0935-9648}, year = {2015}, date = {2015-03-18}, journal = {ADVANCED MATERIALS}, volume = {27}, number = {11}, pages = {1874-+}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {Excellent-performance terahertz (THz) modulators based on graphene/ionic liquid/graphene sandwich structures are demonstrated. The modulation covers a broadband frequency range from 0.1 to 2.5 THz with a modulation depth of up to 99% by applying a small gate voltage of 3 V. The outstanding performance of the proposed devices is due to the conical band structure of the graphene and the powerful gating effect of the ionic liquid in proximity to the graphene.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Excellent-performance terahertz (THz) modulators based on graphene/ionic liquid/graphene sandwich structures are demonstrated. The modulation covers a broadband frequency range from 0.1 to 2.5 THz with a modulation depth of up to 99% by applying a small gate voltage of 3 V. The outstanding performance of the proposed devices is due to the conical band structure of the graphene and the powerful gating effect of the ionic liquid in proximity to the graphene. |
2013 |
Peimyoo, Namphung; Shang, Jingzhi; Cong, Chunxiao; Shen, Xiaonan; Wu, Xiangyang; Yeow, Edwin K L; Yu, Ting Nonblinking, Intense Two-Dimensional Light Emitter: Mono layer WS2 Triangles Journal Article ACS NANO, 7 (12), pp. 10985-10994, 2013, ISSN: 1936-0851. @article{ISI:000329137100059, title = {Nonblinking, Intense Two-Dimensional Light Emitter: Mono layer WS_{2} Triangles}, author = {Namphung Peimyoo and Jingzhi Shang and Chunxiao Cong and Xiaonan Shen and Xiangyang Wu and Edwin K L Yeow and Ting Yu}, doi = {10.1021/nn4046002}, times_cited = {2}, issn = {1936-0851}, year = {2013}, date = {2013-12-01}, journal = {ACS NANO}, volume = {7}, number = {12}, pages = {10985-10994}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {Monolayer WS2 (1L-WS2), with a direct band gap, provides an ideal platform to investigate unique properties of two-dimensional semiconductors. In this work, light emission of a 1L-WS2 triangle has been studied by using steady-state, time-resolved, and temperature-dependent photoluminescence (PL) spectroscopy. Two groups of 1L-WS2 triangles have been grown by chemical vapor deposition, which exhibit nonuniform and uniform PL, respectively. Observed nonuniform PL features, i.e., quenching and blue-shift in certain areas, are caused by structural imperfection and n-doping induced by charged defects. Uniform PL is found to be intrinsic, intense, and nonblinking, which are attributed to high crystalline quality. The binding energy of the A-exciton is extracted experimentally, which gives direct evidence for the large excitonic effect in 1L-WS2. These superior photon emission features make 1L-WS2 an appealing material for optoelectronic applications such as novel light-emitting and biosensing devices.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Monolayer WS2 (1L-WS2), with a direct band gap, provides an ideal platform to investigate unique properties of two-dimensional semiconductors. In this work, light emission of a 1L-WS2 triangle has been studied by using steady-state, time-resolved, and temperature-dependent photoluminescence (PL) spectroscopy. Two groups of 1L-WS2 triangles have been grown by chemical vapor deposition, which exhibit nonuniform and uniform PL, respectively. Observed nonuniform PL features, i.e., quenching and blue-shift in certain areas, are caused by structural imperfection and n-doping induced by charged defects. Uniform PL is found to be intrinsic, intense, and nonblinking, which are attributed to high crystalline quality. The binding energy of the A-exciton is extracted experimentally, which gives direct evidence for the large excitonic effect in 1L-WS2. These superior photon emission features make 1L-WS2 an appealing material for optoelectronic applications such as novel light-emitting and biosensing devices. |
Wu, Yang; Ruan, Xuezhong; Chen, Chih-Hsin; Shin, Young Jun; Lee, Youngbin; Niu, Jing; Liu, Jingbo; Chen, Yuanfu; Yang, Kun-Lin; Zhang, Xinhai; Ahn, Jong-Hyun; Yang, Hyunsoo Graphene/liquid crystal based terahertz phase shifters Journal Article OPTICS EXPRESS, 21 (18), pp. 21395-21402, 2013, ISSN: 1094-4087. @article{ISI:000324867100103, title = {Graphene/liquid crystal based terahertz phase shifters}, author = {Yang Wu and Xuezhong Ruan and Chih-Hsin Chen and Young Jun Shin and Youngbin Lee and Jing Niu and Jingbo Liu and Yuanfu Chen and Kun-Lin Yang and Xinhai Zhang and Jong-Hyun Ahn and Hyunsoo Yang}, doi = {10.1364/OE.21.021395}, times_cited = {0}, issn = {1094-4087}, year = {2013}, date = {2013-09-09}, journal = {OPTICS EXPRESS}, volume = {21}, number = {18}, pages = {21395-21402}, publisher = {OPTICAL SOC AMER}, address = {2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA}, abstract = {Due to its high electrical conductivity and excellent transmittance at terahertz frequencies, graphene is a promising candidate as transparent electrodes for terahertz devices. We demonstrate a liquid crystal based terahertz phase shifter with the graphene films as transparent electrodes. The maximum phase shift is 10.8 degree and the saturation voltage is 5 V with a 50 mu m liquid crystal cell. The transmittance at terahertz frequencies and electrical conductivity depending on the number of graphene layer are also investigated. The proposed phase shifter provides a continuous tunability, fully electrical controllability, and low DC voltage operation. (C) 2013 Optical Society of America}, keywords = {}, pubstate = {published}, tppubtype = {article} } Due to its high electrical conductivity and excellent transmittance at terahertz frequencies, graphene is a promising candidate as transparent electrodes for terahertz devices. We demonstrate a liquid crystal based terahertz phase shifter with the graphene films as transparent electrodes. The maximum phase shift is 10.8 degree and the saturation voltage is 5 V with a 50 mu m liquid crystal cell. The transmittance at terahertz frequencies and electrical conductivity depending on the number of graphene layer are also investigated. The proposed phase shifter provides a continuous tunability, fully electrical controllability, and low DC voltage operation. (C) 2013 Optical Society of America |