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Wang L, Papadopoulos S, Iyikanat F, Zhang J, Huang J, Taniguchi T, Watanabe K, Calame M, Perrin ML, García de Abajo FJ, Novotny L. Exciton-assisted electron tunnelling in van der Waals heterostructures. NATURE MATERIALS 2023; 22:1094-1099. [PMID: 37365227 PMCID: PMC10465355 DOI: 10.1038/s41563-023-01556-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 04/17/2023] [Indexed: 06/28/2023]
Abstract
The control of elastic and inelastic electron tunnelling relies on materials with well-defined interfaces. Two-dimensional van der Waals materials are an excellent platform for such studies. Signatures of acoustic phonons and defect states have been observed in current-to-voltage measurements. These features can be explained by direct electron-phonon or electron-defect interactions. Here we use a tunnelling process that involves excitons in transition metal dichalcogenides (TMDs). We study tunnel junctions consisting of graphene and gold electrodes separated by hexagonal boron nitride with an adjacent TMD monolayer and observe prominent resonant features in current-to-voltage measurements appearing at bias voltages that correspond to TMD exciton energies. By placing the TMD outside of the tunnelling pathway, we demonstrate that this tunnelling process does not require any charge injection into the TMD. The appearance of such optical modes in electrical transport introduces additional functionality towards van der Waals material-based optoelectronic devices.
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Affiliation(s)
- Lujun Wang
- Photonics Laboratory, ETH Zürich, Zürich, Switzerland
| | | | - Fadil Iyikanat
- Institut de Ciències Fotòniques (ICFO), The Barcelona Institute of Science and Technology, Castelldefels, Spain
| | - Jian Zhang
- Transport at Nanoscale Interfaces Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland
| | - Jing Huang
- Photonics Laboratory, ETH Zürich, Zürich, Switzerland
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Michel Calame
- Transport at Nanoscale Interfaces Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland
- Department of Physics, University of Basel, Basel, Switzerland
- Swiss Nanoscience Institute, University of Basel, Basel, Switzerland
| | - Mickael L Perrin
- Transport at Nanoscale Interfaces Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland
- Department of Information Technology and Electrical Engineering, ETH Zürich, Zürich, Switzerland
- Quantum Center, ETH Zürich, Zürich, Switzerland
| | - F Javier García de Abajo
- Institut de Ciències Fotòniques (ICFO), The Barcelona Institute of Science and Technology, Castelldefels, Spain.
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
| | - Lukas Novotny
- Photonics Laboratory, ETH Zürich, Zürich, Switzerland.
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Ripin A, Peng R, Zhang X, Chakravarthi S, He M, Xu X, Fu KM, Cao T, Li M. Tunable phononic coupling in excitonic quantum emitters. NATURE NANOTECHNOLOGY 2023; 18:1020-1026. [PMID: 37264087 DOI: 10.1038/s41565-023-01410-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 04/28/2023] [Indexed: 06/03/2023]
Abstract
Engineering the coupling between fundamental quantum excitations is at the heart of quantum science and technologies. An outstanding case is the creation of quantum light sources in which coupling between single photons and phonons can be controlled and harnessed to enable quantum information transduction. Here we report the deterministic creation of quantum emitters featuring highly tunable coupling between excitons and phonons. The quantum emitters are formed in strain-induced quantum dots created in homobilayer WSe2. The colocalization of quantum-confined interlayer excitons and terahertz interlayer breathing-mode phonons, which directly modulates the exciton energy, leads to a uniquely strong phonon coupling to single-photon emission, with a Huang-Rhys factor reaching up to 6.3. The single-photon spectrum of interlayer exciton emission features a single-photon purity >83% and multiple phonon replicas, each heralding the creation of a phonon Fock state in the quantum emitter. Due to the vertical dipole moment of the interlayer exciton, the phonon-photon interaction is electrically tunable to be higher than the exciton and phonon decoherence rate, and hence promises to reach the strong-coupling regime. Our result demonstrates a solid-state quantum excitonic-optomechanical system at the atomic interface of the WSe2 bilayer that emits flying photonic qubits coupled with stationary phonons, which could be exploited for quantum transduction and interconnection.
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Affiliation(s)
- Adina Ripin
- Department of Physics, University of Washington, Seattle, WA, USA
| | - Ruoming Peng
- Department of Electrical and Computer Engineering, University of Washington, Seattle, WA, USA.
| | - Xiaowei Zhang
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA
| | | | - Minhao He
- Department of Physics, University of Washington, Seattle, WA, USA
| | - Xiaodong Xu
- Department of Physics, University of Washington, Seattle, WA, USA
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA
| | - Kai-Mei Fu
- Department of Physics, University of Washington, Seattle, WA, USA
- Department of Electrical and Computer Engineering, University of Washington, Seattle, WA, USA
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Ting Cao
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA
| | - Mo Li
- Department of Physics, University of Washington, Seattle, WA, USA.
- Department of Electrical and Computer Engineering, University of Washington, Seattle, WA, USA.
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Hennighausen Z, Moon J, McCreary KM, Li CH, van 't Erve OMJ, Jonker BT. Interlayer Exciton-Phonon Bound State in Bi 2Se 3/Monolayer WS 2 van der Waals Heterostructures. ACS NANO 2023; 17:2529-2536. [PMID: 36646115 DOI: 10.1021/acsnano.2c10313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The ability to assemble layers of two-dimensional (2D) materials to form permutations of van der Waals heterostructures provides significant opportunities in materials design and synthesis. Interlayer interactions can enable desired properties and functionality, and understanding such interactions is essential to that end. Here we report formation of interlayer exciton-phonon bound states in Bi2Se3/WS2 heterostructures, where the Bi2Se3 A1(3) surface phonon, a mode particularly susceptible to electron-phonon coupling, is imprinted onto the excitonic emission of the WS2. The exciton-phonon bound state (or exciton-phonon quasiparticle) presents itself as evenly separated peaks superposed on the WS2 excitonic photoluminescence spectrum, whose periodic spacing corresponds to the A1(3) surface phonon energy. Low-temperature polarized Raman spectroscopy of Bi2Se3 reveals intense surface phonons and local symmetry breaking that allows the A1(3) surface phonon to manifest in otherwise forbidden scattering geometries. Our work advances knowledge of the complex interlayer van der Waals interactions and facilitates technologies that combine the distinctive transport and optical properties from separate materials into one device for possible spintronics, valleytronics, and quantum computing applications.
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Affiliation(s)
- Zachariah Hennighausen
- NRC Postdoc at the Materials Science and Technology Division, Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Jisoo Moon
- NRC Postdoc at the Materials Science and Technology Division, Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Kathleen M McCreary
- Materials Science and Technology Division, Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Connie H Li
- Materials Science and Technology Division, Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Olaf M J van 't Erve
- Materials Science and Technology Division, Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Berend T Jonker
- Materials Science and Technology Division, Naval Research Laboratory, Washington, D.C. 20375, United States
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Tan J, Li D, Zhu J, Han N, Gong Y, Zhang Y. Self-trapped excitons in soft semiconductors. NANOSCALE 2022; 14:16394-16414. [PMID: 36317508 DOI: 10.1039/d2nr03935d] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Self-trapped excitons (STEs) have attracted tremendous attention due to their intriguing properties and potential optoelectronic applications. STEs are formed from the lattice distortion induced by the strong electron (exciton)-phonon coupling in soft semiconductors upon photoexcitation, which features in broadband photoluminescence (PL) emission spectra with a large Stokes shift. Recently, significant progress has been achieved in this field but many remain challenges that need to be solved, including the understanding of the underlying physical mechanism, tuning of the performance, and device applications. Along these lines, for the first time, systematic experimental characterizations and advanced theoretical calculations are presented in this review to shed light on the physical mechanism. The possibility of tuning the STEs through multiple degrees of freedom is also presented, along with an overview of the STE-based emerged applications and future research perspectives.
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Affiliation(s)
- Jianbin Tan
- College of Electronics and Information Engineering, Shenzhen University, Shenzhen 518060, P.R. China.
| | - Delong Li
- College of Electronics and Information Engineering, Shenzhen University, Shenzhen 518060, P.R. China.
| | - Jiaqi Zhu
- College of Electronics and Information Engineering, Shenzhen University, Shenzhen 518060, P.R. China.
| | - Na Han
- College of Electronics and Information Engineering, Shenzhen University, Shenzhen 518060, P.R. China.
| | - Youning Gong
- College of Electronics and Information Engineering, Shenzhen University, Shenzhen 518060, P.R. China.
| | - Yupeng Zhang
- College of Electronics and Information Engineering, Shenzhen University, Shenzhen 518060, P.R. China.
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