1
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Wang H, Zhang Z, Huang W, Chen P, He Y, Ming Z, Wang Y, Cheng Z, Shen J, Zhang Z. Programmable Optical Encryption Based on Electrical-Field-Controlled Exciton-Trion Transitions in Monolayer WS 2. ACS APPLIED MATERIALS & INTERFACES 2024. [PMID: 39047193 DOI: 10.1021/acsami.4c06020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
Optical encryption is receiving much attention with the rapid growth of information technology. Conventional optical encryption usually relies on specific configurations, such as metasurface-based holograms and structure colors, not meeting the requirements of increasing dynamic and programmable encryption. Here, we report a programmable optical encryption approach using WS2/SiO2/Au metal-oxide-semiconductor (MOS) devices, which is based on the electrical-field-controlled exciton-trion transitions in monolayer WS2. The modulation depth of the MOS device reflection amplitude up to 25% related to the excitons ensures the fidelity of information, and the decryption based on the near excitonic resonance assures security. With such devices, we successfully demonstrate their applications in real-time encryption of ASCII codes and visual images. For the latter, it can be implemented at the pixel level. The strategy shows significant potential for low-cost, low-energy-consumption, easily integrated, and high-security programmable optical encryptions.
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Affiliation(s)
- Hu Wang
- School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Zheng Zhang
- School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Wentao Huang
- School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Penghao Chen
- School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Yaping He
- School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Ziyu Ming
- School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Yue Wang
- School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Zengguang Cheng
- School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Jiabin Shen
- School of Microelectronics, Fudan University, Shanghai 200433, China
- Institute of Optoelectronics, Fudan University, Shanghai 200433, China
| | - Zengxing Zhang
- School of Microelectronics, Fudan University, Shanghai 200433, China
- National Integrated Circuit Innovation Center, Shanghai 201203, China
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2
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Ağırcan H, Convertino D, Rossi A, Martini L, Pace S, Mishra N, Küster K, Starke U, Kartal Şireli G, Coletti C, Forti S. Determination and investigation of defect domains in multi-shape monolayer tungsten disulfide. NANOSCALE ADVANCES 2024; 6:2850-2859. [PMID: 38817435 PMCID: PMC11134227 DOI: 10.1039/d4na00125g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 04/15/2024] [Indexed: 06/01/2024]
Abstract
Single-layer tungsten disulfide (WS2) is among the most widely investigated two-dimensional materials. Synthesizing it over large areas would enable the exploitation of its appealing optical and electronic properties in industrial applications. However, defects of different nature, concentration and distribution profoundly affect the optical as well as the electronic properties of this crystal. Controlling the defect density distribution can be an effective way to tailor the local dielectric environment and therefore the electronic properties of the system. In this work we investigate the defects in single-layer WS2, grown in different shapes by liquid phase chemical vapor deposition, where the concentration of certain defect species can be controlled by the growth conditions. The properties of the material are surveyed by means of optical spectroscopy, photoelectron spectroscopy and Kelvin probe force microscopy. We determine the chemical nature of the defects and study their influence on the optical and electronic properties of WS2. This work contributes to the understanding of the microscopic nature of the intrinsic defects in WS2, helping the development of defect-based technologies which rely on the control and engineering of defects in dielectric 2D crystals.
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Affiliation(s)
- H Ağırcan
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
- Department of Metallurgical & Materials Engineering Istanbul Technical University 34469 Maslak Istanbul Turkey
| | - D Convertino
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
| | - A Rossi
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
- Graphene Labs, Istituto Italiano di Tecnologia Via Morego 30 16163 Genova Italy
| | - L Martini
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
| | - S Pace
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
- Graphene Labs, Istituto Italiano di Tecnologia Via Morego 30 16163 Genova Italy
| | - N Mishra
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
- Graphene Labs, Istituto Italiano di Tecnologia Via Morego 30 16163 Genova Italy
| | - K Küster
- Max-Planck-Institut für Festkörperforschung Heisenbergstr. 1 70569 Stuttgart Germany
| | - U Starke
- Max-Planck-Institut für Festkörperforschung Heisenbergstr. 1 70569 Stuttgart Germany
| | - G Kartal Şireli
- Department of Metallurgical & Materials Engineering Istanbul Technical University 34469 Maslak Istanbul Turkey
| | - C Coletti
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
- Graphene Labs, Istituto Italiano di Tecnologia Via Morego 30 16163 Genova Italy
| | - S Forti
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
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3
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Mia AK, Meyyappan M, Giri PK. Asymmetric contact-induced selective doping of CVD-grown bilayer WS 2 and its application in high-performance photodetection with an ultralow dark current. NANOSCALE 2024; 16:8583-8596. [PMID: 38602125 DOI: 10.1039/d3nr06118c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2024]
Abstract
Two-dimensional (2D) transition metal dichalcogenides (TMDs) are excellent candidates for high-performance optoelectronics due to their high carrier mobility, air stability and strong optical absorption. However, photodetectors made with monolayer TMDs often exhibit a high dark current, and thus, there is a scope for further improvement. Herein, we developed a 2D bilayer tungsten disulfide (WS2) based photodetector (PD) with asymmetric contacts that exhibits an exceptionally low dark current and high specific detectivity. High-quality and large-area monolayer and bilayer WS2 flakes were synthesized using a thermal chemical vapor deposition system. Compared to conventional symmetric contact electrodes, utilizing metal electrodes with higher and lower work functions relative to bilayer WS2 aids in achieving asymmetric lateral doping in the WS2 flakes. This doping asymmetry was confirmed through the photoluminescence spectral profile and Raman mapping analysis. With the asymmetric contacts on bilayer WS2, we find evidence of selective doping of electrons and holes near the Ti and Au contacts, respectively, while the WS2 region away from the contacts remains intrinsic. When compared with the symmetric contact case, the dark current in the WS2 PD with asymmetric (Au, Ti) contact decreases by an order of magnitude under reverse bias with a concomitant increase in the photocurrent, resulting in an improved on/off ratio of ∼105 and overall improved device performance under identical illumination conditions. We explained this improved performance based on the energy band alignment showing a unidirectional charge flow under light illumination. Our results indicate that the planar device structure and compatibility with current nanofabrication technologies can facilitate its integration into advanced chips for futuristic low-power optoelectronic and nanophotonic applications.
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Affiliation(s)
- Abdul Kaium Mia
- Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati 781039, India.
| | - M Meyyappan
- Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati 781039, India.
| | - P K Giri
- Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati 781039, India.
- Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039, India
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4
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Gomez Sanchez O, Peng GH, Li WH, Shih CH, Chien CH, Cheng SJ. Enhanced Photo-excitation and Angular-Momentum Imprint of Gray Excitons in WSe 2 Monolayers by Spin-Orbit-Coupled Vector Vortex Beams. ACS NANO 2024; 18:11425-11437. [PMID: 38637308 PMCID: PMC11064230 DOI: 10.1021/acsnano.4c01881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 03/22/2024] [Accepted: 04/02/2024] [Indexed: 04/20/2024]
Abstract
A light beam can be spatially structured in the complex amplitude to possess orbital angular momentum (OAM), which introduces an extra degree of freedom alongside the intrinsic spin angular momentum (SAM) associated with circular polarization. Furthermore, superimposing two such twisted light (TL) beams with distinct SAM and OAM produces a vector vortex beam (VVB) in nonseparable states where not only complex amplitude but also polarization is spatially structured and entangled with each other. In addition to the nonseparability, the SAM and OAM in a VVB are intrinsically coupled by the optical spin-orbit interaction and constitute the profound spin-orbit physics in photonics. In this work, we present a comprehensive theoretical investigation, implemented on the first-principles base, of the intriguing light-matter interaction between VVBs and WSe2 monolayers (WSe2-MLs), one of the best-known and promising two-dimensional (2D) materials in optoelectronics dictated by excitons, encompassing bright exciton (BX) as well as various dark excitons (DXs). One of the key findings of our study is that a substantial enhancement of the photoexcitation of gray excitons (GXs), a type of spin-forbidden DX, in a WSe2-ML can be achieved through the utilization of a 3D-structured TL with the optical spin-orbit interaction. Moreover, we show that a spin-orbit-coupled VVB surprisingly allows for the imprinting of the carried optical information onto GXs in 2D materials, which is robust against the decoherence mechanisms in the materials. This suggests a promising method for deciphering the transferred angular momentum from structured light to excitons.
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Affiliation(s)
| | - Guan-Hao Peng
- Department
of Electrophysics, National Yang Ming Chiao
Tung University, Hsinchu 300, Taiwan
| | - Wei-Hua Li
- Department
of Electrophysics, National Yang Ming Chiao
Tung University, Hsinchu 300, Taiwan
| | - Ching-Hung Shih
- Institute
of Electronics, National Yang Ming Chiao
Tung University, Hsinchu 300, Taiwan
| | - Chao-Hsin Chien
- Institute
of Electronics, National Yang Ming Chiao
Tung University, Hsinchu 300, Taiwan
| | - Shun-Jen Cheng
- Department
of Electrophysics, National Yang Ming Chiao
Tung University, Hsinchu 300, Taiwan
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5
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Shin BG, Oh HM, Bae JJ, Song YJ, Lee YH. Charged Exciton Generation by Curvature-Induced Band Gap Fluctuations in Structurally Disordered Two-Dimensional Semiconductors. ACS NANO 2024; 18:10156-10164. [PMID: 38551612 DOI: 10.1021/acsnano.4c00026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
Curvature is a general factor for various two-dimensional (2D) materials due to their flexibility, which is not yet fully unveiled to control their physical properties. In particular, the effect of structural disorder with random curvature formation on excitons in 2D semiconductors is not fully understood. Here, the correlation between structural disorder and exciton formation in monolayer MoS2 on SiO2 was investigated by using photoluminescence (PL) and Raman spectroscopy. We found that the curvature-induced charge localization along with band gap fluctuations aid the formation of the localized charged excitons (such as trions). In the substrate-supported region, the trion population is enhanced by a localized charge due to the microscopic random bending strain, while the trion is suppressed in the suspended region which exhibits negligible bending strain, anomalously even though the dielectric screening effect is lower than that of the supported region. The redistribution of each exciton by the bending strain leads to a huge variation (∼100-fold) in PL intensity between the supported and suspended regions, which cannot be fully comprehended by external potential disorders such as a random distribution of charged impurities. The peak position of PL in MoS2/SiO2 is inversely proportional to the Raman peak position of E12g, indicating that the bending strain is correlated with PL. The supported regions exhibit an indirect portion that was not shown in the suspended regions or atomically flat substrates. The understanding of the structural disorder effect on excitons provides a fundamental path for optoelectronics and strain engineering of 2D semiconductors.
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Affiliation(s)
- Bong Gyu Shin
- Department of Nano Science and Technology, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
| | - Hye Min Oh
- Department of Physics, Kunsan National University, Gunsan, Jeonbuk 54150, Republic of Korea
| | - Jung Jun Bae
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
| | - Young Jae Song
- Department of Nano Science and Technology, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Department of Nano Engineering, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Young Hee Lee
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Department of Energy Science (DOES), Sungkyunkwan University, Suwon 16419, Republic of Korea
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6
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Stellino E, D'Alò B, Blundo E, Postorino P, Polimeni A. Fine-Tuning of the Excitonic Response in Monolayer WS 2 Domes via Coupled Pressure and Strain Variation. NANO LETTERS 2024; 24:3945-3951. [PMID: 38506837 DOI: 10.1021/acs.nanolett.4c00157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
We present a spectroscopic investigation of the vibrational and optoelectronic properties of WS2 domes in the 0-0.65 GPa range. The pressure evolution of the system morphology, deduced by the combined analysis of Raman and photoluminescence spectra, revealed a significant variation in the dome's aspect ratio. The modification of the dome shape caused major changes in the mechanical properties of the system resulting in a sizable increase of the out-of-plane compressive strain while keeping the in-plane tensile strain unchanged. The variation of the strain gradients drives a nonlinear behavior in both the exciton energy and radiative recombination intensity, interpreted as the consequence of a hybridization mechanism between the electronic states of two distinct minima in the conduction band. Our results indicate that pressure and strain can be efficiently combined in low dimensional systems with unconventional morphology to obtain modulations of the electronic band structure not achievable in planar crystals.
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Affiliation(s)
- Elena Stellino
- Department of Basic and Applied Sciences for Engineering, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Beatrice D'Alò
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Elena Blundo
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Paolo Postorino
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Antonio Polimeni
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Roma, Italy
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7
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Banswar D, Sahu RR, Srivatsava R, Hassan MS, Singh S, Sapra S, Das Gupta T, Goswami A, Balasubramanian K. On the unique temperature-dependent interplay of a B-exciton and its trion in monolayer MoSe 2. NANOSCALE 2024; 16:2632-2641. [PMID: 38227478 DOI: 10.1039/d3nr05677e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2024]
Abstract
Plasmonics in metal nanoparticles can enhance their near field optical interaction with matter, promoting emission into selected optical modes. Here, using Ga nanoparticles with carefully tuned plasmonic resonance in proximity to MoSe2 monolayers, we show selective photoluminescence enhancement from the B-exciton and its trion with no observable A-exciton emission. The nanoengineered substrate allows for the first direct experimental observation of the B-trion binding energy in semiconducting monolayers. Using temperature-dependent photoluminescence measurements, we show the following features of the MoSe2 B-exciton family: (i) the trion binding energy has an observable temperature dependence with a decreasing trend towards low temperatures and (ii) the exciton-trion emission ratio varies non-monotonically with temperature with a steep increase in the trion emission at lower temperatures. Using detailed models, we identify the particle size required for selective excitation and describe the underlying physical processes. This opens newer avenues for selectively promoting excitonic species and tuning the effective particle lifetimes in monolayer semiconductors. These results demonstrate the excellent plasmonic properties of Ga nanoparticles, which along with facile processing techniques makes it an attractive alternative to the prevalent noble metal plasmonics having applications in flexible/stretchable materials and textiles.
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Affiliation(s)
- Durgesh Banswar
- Department of Materials Science and Engineering, Indian Institute of Technology, Delhi, India.
| | - Renu Raman Sahu
- Instrumentation and Applied Physics, Indian Institute of Science, Bangalore, India
| | - Rupali Srivatsava
- Department of Materials Science and Engineering, Indian Institute of Technology, Delhi, India.
| | - Md Samim Hassan
- Chemistry Department, Indian Institute of Technology, Delhi, India
| | - Sahil Singh
- Chemistry Department, Indian Institute of Technology, Delhi, India
| | - Sameer Sapra
- Chemistry Department, Indian Institute of Technology, Delhi, India
| | - Tapajyoti Das Gupta
- Instrumentation and Applied Physics, Indian Institute of Science, Bangalore, India
| | - Ankur Goswami
- Department of Materials Science and Engineering, Indian Institute of Technology, Delhi, India.
| | - Krishna Balasubramanian
- Department of Materials Science and Engineering, Indian Institute of Technology, Delhi, India.
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8
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Luo W, Puretzky A, Lawrie B, Tan Q, Gao H, Swan AK, Liang L, Ling X. Improving Strain-localized GaSe Single Photon Emitters with Electrical Doping. NANO LETTERS 2023; 23:9740-9747. [PMID: 37879097 DOI: 10.1021/acs.nanolett.3c02308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
Abstract
Exciton localization through nanoscale strain has been used to create highly efficient single-photon emitters (SPEs) in 2D materials. However, the strong Coulomb interactions between excitons can lead to nonradiative recombination through exciton-exciton annihilation, negatively impacting SPE performance. Here, we investigate the effect of Coulomb interactions on the brightness, single photon purity, and operating temperatures of strain-localized GaSe SPEs by using electrostatic doping. By gating GaSe to the charge neutrality point, the exciton-exciton annihilation nonradiative pathway is suppressed, leading to ∼60% improvement of emission intensity and an enhancement of the single photon purity g(2)(0) from 0.55 to 0.28. The operating temperature also increased from 4.5 K to 85 K consequently. This research provides insight into many-body interactions in excitons confined by nanoscale strain and lays the groundwork for the optimization of SPEs for optoelectronics and quantum photonics.
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Affiliation(s)
- Weijun Luo
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Alexander Puretzky
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Benjamin Lawrie
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Qishuo Tan
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Hongze Gao
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Anna K Swan
- Department of Electrical Engineering, Boston University, Boston, Massachusetts 02215, United States
- The Photonics Center, Boston University, Boston, Massachusetts 02215, United States
- Division of Materials Science and Engineering, Boston University, Boston, Massachusetts 02215, United States
| | - Liangbo Liang
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Xi Ling
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
- The Photonics Center, Boston University, Boston, Massachusetts 02215, United States
- Division of Materials Science and Engineering, Boston University, Boston, Massachusetts 02215, United States
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9
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Zhang S, Sun D, Sun J, Ma K, Wei Z, Park JY, Coffey AH, Zhu C, Dou L, Huang L. Unraveling the Effect of Stacking Configurations on Charge Transfer in WS 2 and Organic Semiconductor Heterojunctions. PRECISION CHEMISTRY 2023; 1:443-451. [PMID: 37771515 PMCID: PMC10526440 DOI: 10.1021/prechem.3c00057] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 06/06/2023] [Accepted: 06/08/2023] [Indexed: 09/30/2023]
Abstract
Photoinduced interfacial charge transfer plays a critical role in energy conversion involving van der Waals (vdW) heterostructures constructed of inorganic nanostructures and organic materials. However, the effect of molecular stacking configurations on charge transfer dynamics is less understood. In this study, we demonstrated the tunability of interfacial charge separation in a type-II heterojunction between monolayer (ML) WS2 and an organic semiconducting molecule [2-(3″',4'-dimethyl-[2,2':5',2':5″,2″'-quaterthiophen]-5-yl)ethan-1-ammonium halide (4Tm)] by rational design of relative stacking configurations. The assembly between ML-WS2 and the 4Tm molecule forms a face-to-face stacking when 4Tm molecules are in a self-aggregation state. In contrast, a face-to-edge stacking is observed when 4Tm molecule is incorporated into a 2D organic-inorganic hybrid perovskite lattice. The face-to-face stacking was proved to be more favorable for hole transfer from WS2 to 4Tm and led to interlayer excitons (IEs) emission. Transient absorption measurements show that the hole transfer occurs on a time scale of 150 fs. On the other hand, the face-to-edge stacking resulted in much slower hole transfer without formation of IEs. This inefficient hole transfer occurs on a similar time scale as A exciton recombination in WS2, leading to the formation of negative trions. These investigations offer important fundamental insights into the charge transfer processes at organic-inorganic interfaces.
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Affiliation(s)
- Shuchen Zhang
- Davidson
School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Dewei Sun
- Department
of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Jiaonan Sun
- Davidson
School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Ke Ma
- Davidson
School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Zitang Wei
- Davidson
School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Jee Yung Park
- Davidson
School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Aidan H. Coffey
- Advanced
Light Source, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - Chenhui Zhu
- Advanced
Light Source, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - Letian Dou
- Davidson
School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
- Birck
Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, United States
| | - Libai Huang
- Department
of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
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10
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Zhang D, Zhai D, Deng S, Yao W, Zhu Q. Single Photon Emitters with Polarization and Orbital Angular Momentum Locking in Monolayer Semiconductors. NANO LETTERS 2023; 23:3851-3857. [PMID: 37104699 DOI: 10.1021/acs.nanolett.3c00459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Excitons in monolayer transition metal dichalcogenide are endowed with intrinsic valley-orbit coupling between their center-of-mass motion and valley pseudospin. When trapped in a confinement potential, e.g., generated by strain field, we find that intralayer excitons are valley and orbital angular momentum (OAM) entangled. By tuning the trap profile and external magnetic field, one can engineer the exciton states at the ground state and realize a series of valley-OAM entangled states. We further show that the OAM of excitons can be transferred to emitted photons, and these novel exciton states can naturally serve as polarization-OAM locked single photon emitters, which under certain circumstance become polarization-OAM entangled, highly tunable by strain trap and magnetic field. Our proposal demonstrates a novel scheme to generate polarization-OAM locked/entangled photons at the nanoscale with a high degree of integrability and tunability, pointing to exciting opportunities for quantum information applications.
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Affiliation(s)
- Di Zhang
- Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, China
- Guangdong-Hong Kong Joint Laboratory of Quantum Matter, Frontier Research Institute for Physics, South China Normal University, Guangzhou 510006, China
| | - Dawei Zhai
- Department of Physics, The University of Hong Kong, Hong Kong, China
- HKU-UCAS Joint Institute of Theoretical and Computational Physics at Hong Kong, Hong Kong, China
| | - Sha Deng
- Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, China
- Guangdong-Hong Kong Joint Laboratory of Quantum Matter, Frontier Research Institute for Physics, South China Normal University, Guangzhou 510006, China
| | - Wang Yao
- Department of Physics, The University of Hong Kong, Hong Kong, China
- HKU-UCAS Joint Institute of Theoretical and Computational Physics at Hong Kong, Hong Kong, China
| | - Qizhong Zhu
- Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, China
- Guangdong-Hong Kong Joint Laboratory of Quantum Matter, Frontier Research Institute for Physics, South China Normal University, Guangzhou 510006, China
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11
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Wang X, Pettes MT, Wang Y, Zhu JX, Dhall R, Song C, Jones AC, Ciston J, Yoo J. Enhanced Exciton-to-Trion Conversion by Proton Irradiation of Atomically Thin WS 2. NANO LETTERS 2023; 23:3754-3761. [PMID: 37094221 DOI: 10.1021/acs.nanolett.2c04987] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Defect engineering of van der Waals semiconductors has been demonstrated as an effective approach to manipulate the structural and functional characteristics toward dynamic device controls, yet correlations between physical properties with defect evolution remain underexplored. Using proton irradiation, we observe an enhanced exciton-to-trion conversion of the atomically thin WS2. The altered excitonic states are closely correlated with nanopore induced atomic displacement, W nanoclusters, and zigzag edge terminations, verified by scanning transmission electron microscopy, photoluminescence, and Raman spectroscopy. Density functional theory calculation suggests that nanopores facilitate formation of in-gap states that act as sinks for free electrons to couple with excitons. The ion energy loss simulation predicts a dominating electron ionization effect upon proton irradiation, providing further evidence on band perturbations and nanopore formation without destroying the overall crystallinity. This study provides a route in tuning the excitonic properties of van der Waals semiconductors using an irradiation-based defect engineering approach.
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Affiliation(s)
- Xuejing Wang
- Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Michael Thompson Pettes
- Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Yongqiang Wang
- Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- Materials Science in Radiation and Dynamics Extremes (MST-8), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Jian-Xin Zhu
- Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- Physics of Condensed Matter and Complex Systems (T-4), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Rohan Dhall
- National Center for Electron Microscopy (NCEM), Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Chengyu Song
- National Center for Electron Microscopy (NCEM), Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Andrew C Jones
- Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Jim Ciston
- National Center for Electron Microscopy (NCEM), Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Jinkyoung Yoo
- Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
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