Fanrong Lin
Position: Grad Students
Affiliation: NUS Centre for Advanced 2D Materials
Research Type: Experiment
Email: fanrong@u.nus.edu
Contact: (65) 8591 2105
CA2DM Publications:
2024 |
Lin, Fanrong; Liu, Jiawei; Lu, Huan; Liu, Xin; Liu, Ying; Hu, Zhili; Lyu, Pin; Zhang, Zhuhua; Martin, Jens; Guo, Wanlin; Liu, Yanpeng Evolution of Graphene Dirac Fermions in Electric Double-Layer Transistors with a Soft Barrier Journal Article ADVANCED FUNCTIONAL MATERIALS, 2024, ISSN: 1616-301X. @article{ISI:001195156600001, title = {Evolution of Graphene Dirac Fermions in Electric Double-Layer Transistors with a Soft Barrier}, author = {Fanrong Lin and Jiawei Liu and Huan Lu and Xin Liu and Ying Liu and Zhili Hu and Pin Lyu and Zhuhua Zhang and Jens Martin and Wanlin Guo and Yanpeng Liu}, doi = {10.1002/adfm.202400553}, times_cited = {0}, issn = {1616-301X}, year = {2024}, date = {2024-04-02}, journal = {ADVANCED FUNCTIONAL MATERIALS}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {The interface and dielectric environment of graphene transistors are of great importance to commercial circuit integrations. The tangling bond in oxide-based dielectric severely lagged the carrier mobility while the 2D dielectric layer (for instance, hexagonal boron nitride) unavoidably hastened complicated condensed physics even at room temperature. Herein, multilayer black phosphorus (BP) a versatile and widely-tunable dielectric candidate for manifesting graphene fermions is demonstrated. Because of hetero-interfacial charge redistributions, a vertical electric double-layer between the bottom BP layer and top graphene spontaneously forms with the central BP layer as a soft barrier. Under dual-gate modulation, abnormal step-like evolution of Dirac fermions and charge-transfer quantum Hall effect arises while the intrinsic Dirac behavior of graphene is preserved, ascribing to the gate-tunable charge redistributions of dielectric BP layer. Moreover, the electric double-layer transistors apply equally well to bilayer graphene with similar Dirac behavior but an enhanced interfacial charge interference. The findings not only create a new avenue to manipulate the fermions by assembling graphene with narrow-gapped 2D layered materials but also promote electric double-layer transistors as a new build block to design multifunctional devices.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The interface and dielectric environment of graphene transistors are of great importance to commercial circuit integrations. The tangling bond in oxide-based dielectric severely lagged the carrier mobility while the 2D dielectric layer (for instance, hexagonal boron nitride) unavoidably hastened complicated condensed physics even at room temperature. Herein, multilayer black phosphorus (BP) a versatile and widely-tunable dielectric candidate for manifesting graphene fermions is demonstrated. Because of hetero-interfacial charge redistributions, a vertical electric double-layer between the bottom BP layer and top graphene spontaneously forms with the central BP layer as a soft barrier. Under dual-gate modulation, abnormal step-like evolution of Dirac fermions and charge-transfer quantum Hall effect arises while the intrinsic Dirac behavior of graphene is preserved, ascribing to the gate-tunable charge redistributions of dielectric BP layer. Moreover, the electric double-layer transistors apply equally well to bilayer graphene with similar Dirac behavior but an enhanced interfacial charge interference. The findings not only create a new avenue to manipulate the fermions by assembling graphene with narrow-gapped 2D layered materials but also promote electric double-layer transistors as a new build block to design multifunctional devices. |
2023 |
Lin, Fanrong; Cao, Zhonghan; Xiao, Feiping; Liu, Jiawei; Qiao, Jiabin; Xue, Minmin; Hu, Zhili; Liu, Ying; Lu, Huan; Zhang, Zhuhua; Martin, Jens; Tong, Qingjun; Guo, Wanlin; Liu, Yanpeng Graphene binding on black phosphorus enables high on/off ratios and mobility Journal Article NATIONAL SCIENCE REVIEW, 11 (2), 2023, ISSN: 2095-5138. @article{ISI:001121789900001, title = {Graphene binding on black phosphorus enables high on/off ratios and mobility}, author = {Fanrong Lin and Zhonghan Cao and Feiping Xiao and Jiawei Liu and Jiabin Qiao and Minmin Xue and Zhili Hu and Ying Liu and Huan Lu and Zhuhua Zhang and Jens Martin and Qingjun Tong and Wanlin Guo and Yanpeng Liu}, doi = {10.1093/nsr/nwad279}, times_cited = {0}, issn = {2095-5138}, year = {2023}, date = {2023-11-03}, journal = {NATIONAL SCIENCE REVIEW}, volume = {11}, number = {2}, publisher = {OXFORD UNIV PRESS}, address = {GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND}, abstract = {Graphene is one of the most promising candidates for integrated circuits due to its robustness against short-channel effects, inherent high carrier mobility and desired gapless nature for Ohmic contact, but it is difficult to achieve satisfactory on/off ratios even at the expense of its carrier mobility, limiting its device applications. Here, we present a strategy to realize high back-gate switching ratios in a graphene monolayer with well-maintained high mobility by forming a vertical heterostructure with a black phosphorus multi-layer. By local current annealing, strain is introduced within an established area of the graphene, which forms a reflective interface with the rest of the strain-free area and thus generates a robust off-state via local current depletion. Applying a positive back-gate voltage to the heterostructure can keep the black phosphorus insulating, while a negative back-gate voltage changes the black phosphorus to be conductive because of hole accumulation. Then, a parallel channel is activated within the strain-free graphene area by edge-contacted electrodes, thereby largely inheriting the intrinsic carrier mobility of graphene in the on-state. As a result, the device can provide an on/off voltage ratio of >103 as well as a mobility of similar to 8000 cm(2) V-1 s(-1) at room temperature, meeting the low-power criterion suggested by the International Roadmap for Devices and Systems.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Graphene is one of the most promising candidates for integrated circuits due to its robustness against short-channel effects, inherent high carrier mobility and desired gapless nature for Ohmic contact, but it is difficult to achieve satisfactory on/off ratios even at the expense of its carrier mobility, limiting its device applications. Here, we present a strategy to realize high back-gate switching ratios in a graphene monolayer with well-maintained high mobility by forming a vertical heterostructure with a black phosphorus multi-layer. By local current annealing, strain is introduced within an established area of the graphene, which forms a reflective interface with the rest of the strain-free area and thus generates a robust off-state via local current depletion. Applying a positive back-gate voltage to the heterostructure can keep the black phosphorus insulating, while a negative back-gate voltage changes the black phosphorus to be conductive because of hole accumulation. Then, a parallel channel is activated within the strain-free graphene area by edge-contacted electrodes, thereby largely inheriting the intrinsic carrier mobility of graphene in the on-state. As a result, the device can provide an on/off voltage ratio of >103 as well as a mobility of similar to 8000 cm(2) V-1 s(-1) at room temperature, meeting the low-power criterion suggested by the International Roadmap for Devices and Systems. |
2020 |
Lin, Fanrong; Qiao, Jiabin; Huang, Junye; Liu, Jiawei; Fu, Deyi; Mayorov, Alexander S; Chen, Hao; Mukherjee, Paromita; Qu, Tingyu; Sow, Chorng-Haur; Watanabe, Kenji; Taniguchi, Takashi; Ozyilmaz, Barbaros Heteromoire Engineering on Magnetic Bloch Transport in Twisted Graphene Superlattices Journal Article NANO LETTERS, 20 (10), pp. 7572-7579, 2020, ISSN: 1530-6984. @article{ISI:000613073900006, title = {Heteromoire Engineering on Magnetic Bloch Transport in Twisted Graphene Superlattices}, author = {Fanrong Lin and Jiabin Qiao and Junye Huang and Jiawei Liu and Deyi Fu and Alexander S Mayorov and Hao Chen and Paromita Mukherjee and Tingyu Qu and Chorng-Haur Sow and Kenji Watanabe and Takashi Taniguchi and Barbaros Ozyilmaz}, doi = {10.1021/acs.nanolett.0c03062}, times_cited = {0}, issn = {1530-6984}, year = {2020}, date = {2020-10-14}, journal = {NANO LETTERS}, volume = {20}, number = {10}, pages = {7572-7579}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {Localized electrons subject to applied magnetic fields can restart to propagate freely through the lattice in delocalized magnetic Bloch states (MBSs) when the lattice periodicity is commensurate with the magnetic length. Twisted graphene superlattices with moire wavelength tunability enable experimental access to the unique delocalization in a controllable fashion. Here, we report the observation and characterization of high-temperature Brown-Zak (BZ) oscillations which come in two types, 1/B and B periodicity, originating from the generation of integer and fractional MBSs, in the twisted bilayer and trilayer graphene superlattices, respectively. Coexisting periodic-in-1/B oscillations assigned to different moire wavelengths are dramatically observed in small-angle twisted bilayer graphene, which may arise from angledisorder-induced in-plane heteromoire superlattices. Moreover, the vertical stacking of heteromoire supercells in double-twisted trilayer graphene results in a mega-sized superlattice. The exotic superlattice contributes to the periodic-in-B oscillation and dominates the magnetic Bloch transport.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Localized electrons subject to applied magnetic fields can restart to propagate freely through the lattice in delocalized magnetic Bloch states (MBSs) when the lattice periodicity is commensurate with the magnetic length. Twisted graphene superlattices with moire wavelength tunability enable experimental access to the unique delocalization in a controllable fashion. Here, we report the observation and characterization of high-temperature Brown-Zak (BZ) oscillations which come in two types, 1/B and B periodicity, originating from the generation of integer and fractional MBSs, in the twisted bilayer and trilayer graphene superlattices, respectively. Coexisting periodic-in-1/B oscillations assigned to different moire wavelengths are dramatically observed in small-angle twisted bilayer graphene, which may arise from angledisorder-induced in-plane heteromoire superlattices. Moreover, the vertical stacking of heteromoire supercells in double-twisted trilayer graphene results in a mega-sized superlattice. The exotic superlattice contributes to the periodic-in-B oscillation and dominates the magnetic Bloch transport. |
Li, Zejun; Zhang, Xiuying; Zhao, Xiaoxu; Li, Jing; Herng, Tun Seng; Xu, Haomin; Lin, Fanrong; Lyu, Pin; Peng, Xinnan; Yu, Wei; Hai, Xiao; Chen, Cheng; Yang, Huimin; Martin, Jens; Lu, Jing; Luo, Xin; Neto, Castro A H; Pennycook, Stephen J; Ding, Jun; Feng, Yuanping; Lu, Jiong Imprinting Ferromagnetism and Superconductivity in Single Atomic Layers of Molecular Superlattices Journal Article ADVANCED MATERIALS, 32 (25), 2020, ISSN: 0935-9648. @article{ISI:000533211300001, title = {Imprinting Ferromagnetism and Superconductivity in Single Atomic Layers of Molecular Superlattices}, author = {Zejun Li and Xiuying Zhang and Xiaoxu Zhao and Jing Li and Tun Seng Herng and Haomin Xu and Fanrong Lin and Pin Lyu and Xinnan Peng and Wei Yu and Xiao Hai and Cheng Chen and Huimin Yang and Jens Martin and Jing Lu and Xin Luo and Castro A H Neto and Stephen J Pennycook and Jun Ding and Yuanping Feng and Jiong Lu}, doi = {10.1002/adma.201907645}, times_cited = {0}, issn = {0935-9648}, year = {2020}, date = {2020-05-17}, journal = {ADVANCED MATERIALS}, volume = {32}, number = {25}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {Ferromagnetism and superconductivity are two antagonistic phenomena since ferromagnetic exchange fields tend to destroy singlet Cooper pairs. Reconciliation of these two competing phases has been achieved in vertically stacked heterostructures where these two orders are confined in different layers. However, controllable integration of these two phases in one atomic layer is a longstanding challenge. Here, an interlayer-space-confined chemical design (ICCD) is reported for the synthesis of dilute single-atom-doped TaS2 molecular superlattice, whereby ferromagnetism is observed in the superconducting TaS2 layers. The intercalation of 2H-TaS2 crystal with bulky organic ammonium molecule expands its van der Waals gap for single-atom doping via co-intercalated cobalt ions, resulting in the formation of quasi-monolayer Co-doped TaS2 superlattices. Isolated Co atoms are decorated in the basal plane of the TaS2 via substituting the Ta atom or anchoring at a hollow site, wherein the orbital-selected p-d hybridization between Co and neighboring Ta and S atoms induces local magnetic moments with strong ferromagnetic coupling. This ICCD approach can be applied to various metal ions, enabling the synthesis of a series of crystal-size TaS2 molecular superlattices.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Ferromagnetism and superconductivity are two antagonistic phenomena since ferromagnetic exchange fields tend to destroy singlet Cooper pairs. Reconciliation of these two competing phases has been achieved in vertically stacked heterostructures where these two orders are confined in different layers. However, controllable integration of these two phases in one atomic layer is a longstanding challenge. Here, an interlayer-space-confined chemical design (ICCD) is reported for the synthesis of dilute single-atom-doped TaS2 molecular superlattice, whereby ferromagnetism is observed in the superconducting TaS2 layers. The intercalation of 2H-TaS2 crystal with bulky organic ammonium molecule expands its van der Waals gap for single-atom doping via co-intercalated cobalt ions, resulting in the formation of quasi-monolayer Co-doped TaS2 superlattices. Isolated Co atoms are decorated in the basal plane of the TaS2 via substituting the Ta atom or anchoring at a hollow site, wherein the orbital-selected p-d hybridization between Co and neighboring Ta and S atoms induces local magnetic moments with strong ferromagnetic coupling. This ICCD approach can be applied to various metal ions, enabling the synthesis of a series of crystal-size TaS2 molecular superlattices. |
Cao, Zhonghan; Lin, Fanrong; Gong, Gu; Chen, Hao; Martin, Jens Low Schottky barrier contacts to 2H-MoS2 by Sn electrodes Journal Article APPLIED PHYSICS LETTERS, 116 (2), 2020, ISSN: 0003-6951. @article{ISI:000518029000024, title = {Low Schottky barrier contacts to 2H-MoS_{2} by Sn electrodes}, author = {Zhonghan Cao and Fanrong Lin and Gu Gong and Hao Chen and Jens Martin}, doi = {10.1063/1.5094890}, times_cited = {0}, issn = {0003-6951}, year = {2020}, date = {2020-01-13}, journal = {APPLIED PHYSICS LETTERS}, volume = {116}, number = {2}, publisher = {AMER INST PHYSICS}, address = {1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA}, abstract = {The semiconductor MoS2 has attracted much attention owing to its sizable energy bandgap, significant spin-orbit coupling, and quantum effects such as the valley Hall effect and gate-induced superconductivity. However, in electronic devices, the energy bandgap usually gives rise to the formation of Schottky barriers at the interface to the contact metal, which may render devices intended for quantum transport inapplicable at low temperature. Therefore, the fabrication of Ohmic contacts operational at low temperature is crucial. Yet, it currently remains a substantial challenge to produce low resistive contacts with a simple process. We manifest that low temperature Ohmic contacts to mono- and few-layer MoS2 can be achieved with Tin (Sn) as the contact metal. Sn is directly evaporated onto MoS2, and hence, this establishes a much easier fabrication method than tunneling barriers, for example. We provide detailed device characterization, extract Schottky barrier heights, demonstrate multiterminal measurements, and propose a possible explanation: strain induced deformation of MoS2 imposed by Sn. Published under license by AIP Publishing.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The semiconductor MoS2 has attracted much attention owing to its sizable energy bandgap, significant spin-orbit coupling, and quantum effects such as the valley Hall effect and gate-induced superconductivity. However, in electronic devices, the energy bandgap usually gives rise to the formation of Schottky barriers at the interface to the contact metal, which may render devices intended for quantum transport inapplicable at low temperature. Therefore, the fabrication of Ohmic contacts operational at low temperature is crucial. Yet, it currently remains a substantial challenge to produce low resistive contacts with a simple process. We manifest that low temperature Ohmic contacts to mono- and few-layer MoS2 can be achieved with Tin (Sn) as the contact metal. Sn is directly evaporated onto MoS2, and hence, this establishes a much easier fabrication method than tunneling barriers, for example. We provide detailed device characterization, extract Schottky barrier heights, demonstrate multiterminal measurements, and propose a possible explanation: strain induced deformation of MoS2 imposed by Sn. Published under license by AIP Publishing. |
2019 |
Wang, Junyong; Lin, Fanrong; Verzhbitskiy, Ivan; Watanabe, Kenji; Taniguchi, Takashi; Martin, Jens; Eda, Gold Polarity Tunable Trionic Electroluminescence in Monolayer WSe2 Journal Article NANO LETTERS, 19 (10), pp. 7470-7475, 2019, ISSN: 1530-6984. @article{ISI:000490353500097, title = {Polarity Tunable Trionic Electroluminescence in Monolayer WSe_{2}}, author = {Junyong Wang and Fanrong Lin and Ivan Verzhbitskiy and Kenji Watanabe and Takashi Taniguchi and Jens Martin and Gold Eda}, doi = {10.1021/acs.nanolett.9b03215}, times_cited = {0}, issn = {1530-6984}, year = {2019}, date = {2019-10-01}, journal = {NANO LETTERS}, volume = {19}, number = {10}, pages = {7470-7475}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {Monolayer WSe2 exhibits luminescence arising from various types of exciton complexes due to strong many-body effects. Here, we demonstrate selective electrical excitation of positive and negative trions in van der Waals metal-insulator-semiconductor (MIS) heterostructure consisting of few-layer graphene (FLG), hexagonal boron nitride (hBN), and monolayer WSe2. Intentional unbalanced injection of electrons and holes is achieved via field-emission tunneling and electrostatic accumulation. The device exhibits planar electroluminescence from either positive trion X+ or negative trion X- depending on the bias conditions. We show that hBN serves as a tunneling barrier material allowing selective injection of electron or holes into WSe2 from FLG layer. Our observation offers prospects for hot carrier injection, trion manipulation, and on-chip excitonic devices based on two-dimensional semiconductors.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Monolayer WSe2 exhibits luminescence arising from various types of exciton complexes due to strong many-body effects. Here, we demonstrate selective electrical excitation of positive and negative trions in van der Waals metal-insulator-semiconductor (MIS) heterostructure consisting of few-layer graphene (FLG), hexagonal boron nitride (hBN), and monolayer WSe2. Intentional unbalanced injection of electrons and holes is achieved via field-emission tunneling and electrostatic accumulation. The device exhibits planar electroluminescence from either positive trion X+ or negative trion X- depending on the bias conditions. We show that hBN serves as a tunneling barrier material allowing selective injection of electron or holes into WSe2 from FLG layer. Our observation offers prospects for hot carrier injection, trion manipulation, and on-chip excitonic devices based on two-dimensional semiconductors. |