1
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Wang H, Xia H, Liu Y, Chen Y, Xie R, Wang Z, Wang P, Miao J, Wang F, Li T, Fu L, Martyniuk P, Xu J, Hu W, Lu W. Room-temperature low-threshold avalanche effect in stepwise van-der-Waals homojunction photodiodes. Nat Commun 2024; 15:3639. [PMID: 38684745 PMCID: PMC11059283 DOI: 10.1038/s41467-024-47958-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 04/16/2024] [Indexed: 05/02/2024] Open
Abstract
Avalanche or carrier-multiplication effect, based on impact ionization processes in semiconductors, has a great potential for enhancing the performance of photodetector and solar cells. However, in practical applications, it suffers from high threshold energy, reducing the advantages of carrier multiplication. Here, we report on a low-threshold avalanche effect in a stepwise WSe2 structure, in which the combination of weak electron-phonon scattering and high electric fields leads to a low-loss carrier acceleration and multiplication. Owing to this effect, the room-temperature threshold energy approaches the fundamental limit, Ethre ≈ Eg, where Eg is the bandgap of the semiconductor. Our findings offer an alternative perspective on the design and fabrication of future avalanche and hot-carrier photovoltaic devices.
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Affiliation(s)
- Hailu Wang
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hui Xia
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Yaqian Liu
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, China
| | - Yue Chen
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Runzhang Xie
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhen Wang
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Peng Wang
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jinshui Miao
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Fang Wang
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Tianxin Li
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lan Fu
- Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT, 2601, Australia
| | - Piotr Martyniuk
- Institute of Applied Physics, Military University of Technology, 2 Kaliskiego St., 00-908, Warsaw, Poland
| | - Jianbin Xu
- Department of Electronic Engineering and Materials Science and Technology Research Center, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Weida Hu
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Wei Lu
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
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2
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Weerdenburg S, Singh N, van der Laan M, Kinge S, Schall P, Siebbeles LDA. New Theoretical Model to Describe Carrier Multiplication in Semiconductors: Explanation of Disparate Efficiency in MoTe 2 versus PbS and PbSe. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2024; 128:3693-3702. [PMID: 38476826 PMCID: PMC10926152 DOI: 10.1021/acs.jpcc.4c00383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 02/16/2024] [Accepted: 02/20/2024] [Indexed: 03/14/2024]
Abstract
We present a theoretical model to compute the efficiency of the generation of two or more electron-hole pairs in a semiconductor by the absorption of one photon via the process of carrier multiplication (CM). The photogeneration quantum yield of electron-hole pairs is calculated from the number of possible CM decay pathways of the electron and the hole. We apply our model to investigate the underlying cause of the high efficiency of CM in bulk 2H-MoTe2, as compared to bulk PbS and PbSe. Electronic band structures were calculated with density functional theory, from which the number of possible CM decay pathways was calculated for all initial electron and hole states that can be produced at a given photon energy. The variation of the number of CM pathways with photon energy reflects the dependence of experimental CM quantum yields on the photon energy and material composition. We quantitatively reproduce experimental CM quantum yields for MoTe2, PbS, and PbSe from the calculated number of CM pathways and one adjustable fit parameter. This parameter is related to the ratio of Coulomb coupling matrix elements and the cooling rate of the electrons and holes. Large variations of this fit parameter result in small changes in the modeled quantum yield for MoTe2, which confirms that its high CM efficiency can be mainly attributed to its extraordinary large number of CM pathways. The methodology of this work can be applied to analyze or predict the CM efficiency of other materials.
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Affiliation(s)
- Sven Weerdenburg
- Chemical
Engineering Department, Delft University
of Technology, Van der Maasweg 9, Delft 2629 HZ, The Netherlands
| | - Nisha Singh
- Chemical
Engineering Department, Delft University
of Technology, Van der Maasweg 9, Delft 2629 HZ, The Netherlands
| | - Marco van der Laan
- Institute
of Physics, University of Amsterdam, Amsterdam 1098 XH, The Netherlands
| | - Sachin Kinge
- Materials
Research & Development, Toyota Motor
Europe, Zaventem B1930, Belgium
| | - Peter Schall
- Institute
of Physics, University of Amsterdam, Amsterdam 1098 XH, The Netherlands
| | - Laurens D. A. Siebbeles
- Chemical
Engineering Department, Delft University
of Technology, Van der Maasweg 9, Delft 2629 HZ, The Netherlands
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3
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Song S, Yoon A, Jang S, Lynch J, Yang J, Han J, Choe M, Jin YH, Chen CY, Cheon Y, Kwak J, Jeong C, Cheong H, Jariwala D, Lee Z, Kwon SY. Fabrication of p-type 2D single-crystalline transistor arrays with Fermi-level-tuned van der Waals semimetal electrodes. Nat Commun 2023; 14:4747. [PMID: 37550303 PMCID: PMC10406929 DOI: 10.1038/s41467-023-40448-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Accepted: 07/26/2023] [Indexed: 08/09/2023] Open
Abstract
High-performance p-type two-dimensional (2D) transistors are fundamental for 2D nanoelectronics. However, the lack of a reliable method for creating high-quality, large-scale p-type 2D semiconductors and a suitable metallization process represents important challenges that need to be addressed for future developments of the field. Here, we report the fabrication of scalable p-type 2D single-crystalline 2H-MoTe2 transistor arrays with Fermi-level-tuned 1T'-phase semimetal contact electrodes. By transforming polycrystalline 1T'-MoTe2 to 2H polymorph via abnormal grain growth, we fabricated 4-inch 2H-MoTe2 wafers with ultra-large single-crystalline domains and spatially-controlled single-crystalline arrays at a low temperature (~500 °C). Furthermore, we demonstrate on-chip transistors by lithographic patterning and layer-by-layer integration of 1T' semimetals and 2H semiconductors. Work function modulation of 1T'-MoTe2 electrodes was achieved by depositing 3D metal (Au) pads, resulting in minimal contact resistance (~0.7 kΩ·μm) and near-zero Schottky barrier height (~14 meV) of the junction interface, and leading to high on-state current (~7.8 μA/μm) and on/off current ratio (~105) in the 2H-MoTe2 transistors.
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Affiliation(s)
- Seunguk Song
- Department of Materials Science and Engineering & Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, US
| | - Aram Yoon
- Department of Materials Science and Engineering & Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS), Ulsan, 44919, Republic of Korea
| | - Sora Jang
- Department of Materials Science and Engineering & Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Jason Lynch
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, US
| | - Jihoon Yang
- Department of Materials Science and Engineering & Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Juwon Han
- Department of Materials Science and Engineering & Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Myeonggi Choe
- Department of Materials Science and Engineering & Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS), Ulsan, 44919, Republic of Korea
| | - Young Ho Jin
- Department of Materials Science and Engineering & Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Cindy Yueli Chen
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, US
| | - Yeryun Cheon
- Department of Physics, Sogang University, Seoul, 04107, Republic of Korea
| | - Jinsung Kwak
- Department of Materials Science and Engineering & Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
- Department of Physics, Changwon National University, Changwon, 51140, Republic of Korea
| | - Changwook Jeong
- Department of Materials Science and Engineering & Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Hyeonsik Cheong
- Department of Physics, Sogang University, Seoul, 04107, Republic of Korea
| | - Deep Jariwala
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, US
| | - Zonghoon Lee
- Department of Materials Science and Engineering & Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea.
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS), Ulsan, 44919, Republic of Korea.
| | - Soon-Yong Kwon
- Department of Materials Science and Engineering & Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea.
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4
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Jang YJ, Paul KK, Park JC, Kim M, Tran MD, Song HY, Yun SJ, Lee H, Enkhbat T, Kim J, Lee YH, Kim JH. Boosting internal quantum efficiency via ultrafast triplet transfer to 2H-MoTe 2 film. SCIENCE ADVANCES 2023; 9:eadg2324. [PMID: 37343104 DOI: 10.1126/sciadv.adg2324] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 05/16/2023] [Indexed: 06/23/2023]
Abstract
Organic systems often allow to create two triplet spin states (triplet excitons) by converting an initially excited singlet spin state (a singlet exciton). An ideally designed organic/inorganic heterostructure could reach the photovoltaic energy harvest over the Shockley-Queisser (S-Q) limit because of the efficient conversion of triplet excitons into charge carriers. Here, we demonstrate the molybdenum ditelluride (MoTe2)/pentacene heterostructure to boost the carrier density via efficient triplet transfer from pentacene to MoTe2 using ultrafast transient absorption spectroscopy. We observe carrier multiplication by nearly four times by doubling carriers in MoTe2 via the inverse Auger process and subsequently doubling carriers via triplet extraction from pentacene. We also verify efficient energy conversion by doubling the photocurrent in the MoTe2/pentacene film. This puts a step forward to enhancing photovoltaic conversion efficiency beyond the S-Q limit in the organic/inorganic heterostructures.
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Affiliation(s)
- Yu Jin Jang
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Kamal Kumar Paul
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jin Cheol Park
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Meeree Kim
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Department of Chemistry, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Minh Dao Tran
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Hyun Yong Song
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Seok Joon Yun
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Hyoyoung Lee
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Chemistry, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Temujin Enkhbat
- Department of Physics, Incheon National University, Incheon 22012, Republic of Korea
| | - JunHo Kim
- Department of Physics, Incheon National University, Incheon 22012, 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, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Ji-Hee Kim
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
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5
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Wang T, Hopper TR, Mondal N, Liu S, Yao C, Zheng X, Torrisi F, Bakulin AA. Hot Carrier Cooling and Trapping in Atomically Thin WS 2 Probed by Three-Pulse Femtosecond Spectroscopy. ACS NANO 2023; 17:6330-6340. [PMID: 36939760 PMCID: PMC10100566 DOI: 10.1021/acsnano.2c10479] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 03/14/2023] [Indexed: 06/18/2023]
Abstract
Transition metal dichalcogenides (TMDs) have shown outstanding semiconducting properties which make them promising materials for next-generation optoelectronic and electronic devices. These properties are imparted by fundamental carrier-carrier and carrier-phonon interactions that are foundational to hot carrier cooling. Recent transient absorption studies have reported ultrafast time scales for carrier cooling in TMDs that can be slowed at high excitation densities via a hot-phonon bottleneck (HPB) and discussed these findings in the light of optoelectronic applications. However, quantitative descriptions of the HPB in TMDs, including details of the electron-lattice coupling and how cooling is affected by the redistribution of energy between carriers, are still lacking. Here, we use femtosecond pump-push-probe spectroscopy as a single approach to systematically characterize the scattering of hot carriers with optical phonons, cold carriers, and defects in a benchmark TMD monolayer of polycrystalline WS2. By controlling the interband pump and intraband push excitations, we observe, in real-time (i) an extremely rapid "intrinsic" cooling rate of ∼18 ± 2.7 eV/ps, which can be slowed with increasing hot carrier density, (ii) the deprecation of this HPB at elevated cold carrier densities, exposing a previously undisclosed role of the carrier-carrier interactions in mediating cooling, and (iii) the interception of high energy hot carriers on the subpicosecond time scale by lattice defects, which may account for the lower photoluminescence yield of TMDs when excited above band gap.
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Affiliation(s)
- Tong Wang
- Department
of Chemistry and Centre for Processable Electronics, Imperial College London, London W12 0BZ, United Kingdom
| | - Thomas R. Hopper
- Department
of Chemistry and Centre for Processable Electronics, Imperial College London, London W12 0BZ, United Kingdom
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
| | - Navendu Mondal
- Department
of Chemistry and Centre for Processable Electronics, Imperial College London, London W12 0BZ, United Kingdom
| | - Sihui Liu
- Department
of Chemistry and Centre for Processable Electronics, Imperial College London, London W12 0BZ, United Kingdom
| | - Chengning Yao
- Department
of Chemistry and Centre for Processable Electronics, Imperial College London, London W12 0BZ, United Kingdom
| | - Xijia Zheng
- Department
of Chemistry and Centre for Processable Electronics, Imperial College London, London W12 0BZ, United Kingdom
| | - Felice Torrisi
- Department
of Chemistry and Centre for Processable Electronics, Imperial College London, London W12 0BZ, United Kingdom
- Dipartimento
di Fisica e Astronomia, Universita’
di Catania & CNR-IMM (Catania Universita’), Via S. Sofia 64, 95123 Catania, Italy
| | - Artem A. Bakulin
- Department
of Chemistry and Centre for Processable Electronics, Imperial College London, London W12 0BZ, United Kingdom
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6
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Soni A, Kushavah D, Lu LS, Chang WH, Pal SK. Efficient Multiple Exciton Generation in Monolayer MoS 2. J Phys Chem Lett 2023; 14:2965-2972. [PMID: 36939637 DOI: 10.1021/acs.jpclett.3c00306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Utilization of the excess energy of photoexcitation that is otherwise lost as thermal effects can improve the efficiency of next-generation light-harvesting devices. Multiple exciton generation (MEG) in semiconducting materials yields two or more excitons by absorbing a single high-energy photon, which can break the Shockley-Queisser limit for the conversion efficiency of photovoltaic devices. Recently, monolayer transition metal dichalcogenides (TMDs) have emerged as promising light-harvesting materials because of their high absorption coefficient. Here, we report efficient MEGs with low threshold energy and high (86%) efficiency in a van der Waals (vdW) layered material, MoS2. Through different experimental approaches, we demonstrate the signature of exciton multiplication and discuss the possible origin of decisive MEG in monolayer MoS2. Our results reveal that vdW-layered materials could be a potential candidate for developing mechanically flexible and highly efficient next-generation solar cells and photodetectors.
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Affiliation(s)
- Ashish Soni
- School of Physical Sciences, Indian Institute of Technology Mandi, Kamand, Mandi 175005, Himachal Pradesh, India
- Advanced Materials Research Centre, Indian Institute of Technology Mandi, Kamand, Mandi 175005, Himachal Pradesh, India
| | - Dushyant Kushavah
- School of Physical Sciences, Indian Institute of Technology Mandi, Kamand, Mandi 175005, Himachal Pradesh, India
- Advanced Materials Research Centre, Indian Institute of Technology Mandi, Kamand, Mandi 175005, Himachal Pradesh, India
| | - Li-Syuan Lu
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
| | - Wen-Hao Chang
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
- Research Center for Applied Sciences, Academia Sinica, Nankang, Taipei 11529, Taiwan
| | - Suman Kalyan Pal
- School of Physical Sciences, Indian Institute of Technology Mandi, Kamand, Mandi 175005, Himachal Pradesh, India
- Advanced Materials Research Centre, Indian Institute of Technology Mandi, Kamand, Mandi 175005, Himachal Pradesh, India
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7
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Kang C, Choi H, Son H, Kang T, Lee SM, Lee S. A steep-switching impact ionization-based threshold switching field-effect transistor. NANOSCALE 2023; 15:5771-5777. [PMID: 36857633 DOI: 10.1039/d2nr06547a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
A steep switching device with a low subthreshold swing (SS) that overcomes the fundamental Boltzmann limit (kT/q) is required to efficiently process a continuously increasing amount of data. Recently, two-dimensional material-based impact ionization transistors with various structures have been reported with the advantages of a low critical electric field and a unique quantum confinement effect. However, most of them cannot retain steep switching at room temperature, and device performance degradation issues caused by impact ionization-induced hot carriers have not been structurally addressed. In this study, we presented an impact-ionization-based threshold switching field-effect transistor (I2S-FET) fabricated with a serial connection of a MoS2 FET and WSe2 impact ionization-based threshold switch (I2S). We obtained repetitive operation with low SS (32.8 mV dec-1) at room temperature, along with low dielectric injection efficiency (10-6), through a structural design with separation of the conducting region, which determines on-state carrier transport, and the steep-switching region where the transition from off- to on-state occurs via impact ionization. Furthermore, compared to previously reported threshold-switching devices, our device demonstrated hysteresis-free switching characteristics. This study provides a promising approach for developing next-generation energy-efficient electronic devices and ultralow-power applications.
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Affiliation(s)
- Chanwoo Kang
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SSKU), Suwon 16419, Korea.
| | - Haeju Choi
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SSKU), Suwon 16419, Korea.
| | - Hyeonje Son
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SSKU), Suwon 16419, Korea.
| | - Taeho Kang
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SSKU), Suwon 16419, Korea.
| | - Sang-Min Lee
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SSKU), Suwon 16419, Korea.
| | - Sungjoo Lee
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University (SSKU), Suwon 16419, Korea.
- Department of Nano Science and Technology, Sungkyunkwan University, Suwon 16419, Korea
- Department of Nano Engineering, Sungkyunkwan University, Suwon 16419, Korea
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8
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Kang T, Choi H, Li J, Kang C, Hwang E, Lee S. Anisotropy of impact ionization in WSe 2 field effect transistors. NANO CONVERGENCE 2023; 10:13. [PMID: 36932269 PMCID: PMC10023822 DOI: 10.1186/s40580-023-00361-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 02/15/2023] [Indexed: 06/18/2023]
Abstract
Carrier multiplication via impact ionization in two-dimensional (2D) layered materials is a very promising process for manufacturing high-performance devices because the multiplication has been reported to overcome thermodynamic conversion limits. Given that 2D layered materials exhibit highly anisotropic transport properties, understanding the directionally-dependent multiplication process is necessary for device applications. In this study, the anisotropy of carrier multiplication in the 2D layered material, WSe2, is investigated. To study the multiplication anisotropy of WSe2, both lateral and vertical WSe2 field effect transistors (FETs) are fabricated and their electrical and transport properties are investigated. We find that the multiplication anisotropy is much bigger than the transport anisotropy, i.e., the critical electric field (ECR) for impact ionization of vertical WSe2 FETs is approximately ten times higher than that of lateral FETs. To understand the experimental results we calculate the average energy of the carriers in the proposed devices under strong electric fields by using the Monte Carlo simulation method. The calculated average energy is strongly dependent on the transport directions and we find that the critical electric field for impact ionization in vertical devices is approximately one order of magnitude larger than that of the lateral devices, consistent with experimental results. Our findings provide new strategies for the future development of low-power electric and photoelectric devices.
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Affiliation(s)
- Taeho Kang
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, South Korea
- Department of Nano Science and Technology, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Haeju Choi
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, South Korea
- Department of Nano Science and Technology, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Jinshu Li
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, South Korea
- Department of Nano Science and Technology, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Chanwoo Kang
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, South Korea
- Department of Nano Science and Technology, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Euyheon Hwang
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, South Korea.
- Department of Nano Science and Technology, Sungkyunkwan University, Suwon, 16419, South Korea.
- Department of Nano Engineering, Sungkyunkwan University, Suwon, 16419, South Korea.
| | - Sungjoo Lee
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, South Korea.
- Department of Nano Science and Technology, Sungkyunkwan University, Suwon, 16419, South Korea.
- Department of Nano Engineering, Sungkyunkwan University, Suwon, 16419, South Korea.
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9
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Yu X, Dai Y, Lu Y, Liu C, Yan Y, Shen R, Yang Z, Feng L, Sun L, Liu Y, Lin S. High Efficient Solar Cell Based on Heterostructure Constructed by Graphene and GaAs Quantum Wells. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2204058. [PMID: 36394152 PMCID: PMC9839879 DOI: 10.1002/advs.202204058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 10/10/2022] [Indexed: 06/16/2023]
Abstract
Despite the fascinating optoelectronic properties of graphene, the power conversion efficiency (PCE) of graphene based solar cells remains to be lifted up. Herein, it is experimentally shown that the graphene/quantum wells/GaAs heterostructure solar cell can reach a PCE of 20.2% and an open-circuit voltage (Voc ) as high as 1.16 V at 90 K. The high efficiency is a result of carrier multiplication (CM) effect of graphene in the graphene/GaAs heterostructure. Especially, the external quantum efficiency (EQE) in the ultraviolet wavelength can be improved up to 72.2% based on the heterostructure constructed by graphene/In0.15 Ga0.85 As/GaAs0.75 P0.25 quantum wells/GaAs. The EQE increases as the light wavelength decreases, which indicates more carriers can be effectively excited by the higher energy photons through CM effect. Owing to these physical characters, the graphene/GaAs heterostructure solar cell will provide a possible way to exceed Shockley-Queisser (S-Q) limit.
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Affiliation(s)
- Xutao Yu
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Yue Dai
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Yanghua Lu
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Chang Liu
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Yanfei Yan
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Runjiang Shen
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Zunshan Yang
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Lixuan Feng
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Lijie Sun
- State Key Laboratory of Space Power Technology, Shanghai Institute of Space Power Sources, Shanghai, 200245, P. R. China
| | - Yong Liu
- State Key Laboratory of Space Power Technology, Shanghai Institute of Space Power Sources, Shanghai, 200245, P. R. China
| | - Shisheng Lin
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 310027, P. R. China
- State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou, 310027, P. R. China
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10
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Liu Y, Frauenheim T, Yam C. Carrier Multiplication in Transition Metal Dichalcogenides Beyond Threshold Limit. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2203400. [PMID: 36071030 PMCID: PMC9631089 DOI: 10.1002/advs.202203400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 08/01/2022] [Indexed: 06/15/2023]
Abstract
Carrier multiplication (CM), multiexciton generation by absorbing a single photon, enables disruptive improvements in photovoltaic conversion efficiency. However, energy conservation constrains the threshold energy to at least twice bandgap (2 E g $ E_\text{g}$ ). Here, a below threshold limit CM in monolayer transition metal dichalcogenides (TMDCs) is reported. Surprisingly, CM is observed with excitation energy of only 1.75 E g $E_\text{g}$ due to lattice vibrations. Electron-phonon coupling (EPC) results in significant changes in electronic structures, which favors CM. Indeed, the strongest EPC in monolayer MoS2 leads to the most efficient CM among the studied TMDCs. For practical applications, chalcogen vacancies can further lower the threshold by introducing defect states within bandgap. In particular, for monolayer WS2 , CM occurs with excitation energy as low as 1.51 E g $E_\text{g}$ . The results identify TMDCs as attractive candidate materials for efficient optoelectronic devices with the advantages of high photoconductivity and efficient CM.
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Affiliation(s)
- Yuxiang Liu
- Bremen Center for Computational Materials ScienceUniversity of BremenAm Fallturm 128359BremenGermany
| | - Thomas Frauenheim
- Bremen Center for Computational Materials ScienceUniversity of BremenAm Fallturm 128359BremenGermany
- Beijing Computational Science Research CenterHaidian DistrictBeijing100193China
- Shenzhen JL Computational Science and Applied Research InstituteShenzhen518109China
| | - ChiYung Yam
- Shenzhen Institute for Advanced StudyUniversity of Electronic Science and Technology of ChinaShenzhen518000China
- Hong Kong Quantum AI Lab LimitedHong Kong0000China
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11
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Huang Z, Beard MC. Dye-Sensitized Multiple Exciton Generation in Lead Sulfide Quantum Dots. J Am Chem Soc 2022; 144:15855-15861. [PMID: 35981268 PMCID: PMC9437916 DOI: 10.1021/jacs.2c07109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Multiple exciton generation (MEG), the generation of multiple excitons from the absorption of a single high-energy photon, is a strategy to go beyond the limiting efficiencies that define current-day solar cells by harvesting some of the thermalization energy losses that occur when photons with an energy greater than the semiconductor bandgap are absorbed. In this work, we show that organic dyes can sensitize MEG in semiconductor quantum dots (QDs). In particular, we found that surface-anchored pyrene ligands enhanced the photon-to-charge carrier quantum yield of PbS QDs from 113 ± 3% to 183 ± 7% when the photon energy was 3.9 times the band gap. A wavelength dependence study shows that the enhancement is positively correlated with the pyrene absorptivity. Transient absorption and steady-state photoluminescence measurements suggest that the MEG sensitization is based on an initial fast electron transfer from the pyrene ligands to the PbS QDs producing hot-electrons in the QDs that subsequently undergo MEG. This work demonstrates that hybrid and synergistic organic/inorganic interactions can be a successful strategy to enhance MEG.
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Affiliation(s)
- Zhiyuan Huang
- Chemistry & Nanoscience Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Matthew C Beard
- Chemistry & Nanoscience Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
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12
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Lin H, Zhang Z, Zhang H, Lin KT, Wen X, Liang Y, Fu Y, Lau AKT, Ma T, Qiu CW, Jia B. Engineering van der Waals Materials for Advanced Metaphotonics. Chem Rev 2022; 122:15204-15355. [PMID: 35749269 DOI: 10.1021/acs.chemrev.2c00048] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The outstanding chemical and physical properties of 2D materials, together with their atomically thin nature, make them ideal candidates for metaphotonic device integration and construction, which requires deep subwavelength light-matter interaction to achieve optical functionalities beyond conventional optical phenomena observed in naturally available materials. In addition to their intrinsic properties, the possibility to further manipulate the properties of 2D materials via chemical or physical engineering dramatically enhances their capability, evoking new science on light-matter interaction, leading to leaped performance of existing functional devices and giving birth to new metaphotonic devices that were unattainable previously. Comprehensive understanding of the intrinsic properties of 2D materials, approaches and capabilities for chemical and physical engineering methods, the resulting property modifications and novel functionalities, and applications of metaphotonic devices are provided in this review. Through reviewing the detailed progress in each aspect and the state-of-the-art achievement, insightful analyses of the outstanding challenges and future directions are elucidated in this cross-disciplinary comprehensive review with the aim to provide an overall development picture in the field of 2D material metaphotonics and promote rapid progress in this fast emerging and prosperous field.
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Affiliation(s)
- Han Lin
- School of Science, RMIT University, Melbourne, Victoria 3000, Australia.,The Australian Research Council (ARC) Industrial Transformation Training, Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
| | - Zhenfang Zhang
- School of Textile Science and Engineering, Xi'an Polytechnic University, Xi'an 710048, China
| | - Huihui Zhang
- Centre for Translational Atomaterials, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria 3122, Australia
| | - Keng-Te Lin
- School of Science, RMIT University, Melbourne, Victoria 3000, Australia
| | - Xiaoming Wen
- Centre for Translational Atomaterials, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria 3122, Australia
| | - Yao Liang
- Centre for Translational Atomaterials, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria 3122, Australia
| | - Yang Fu
- Centre for Translational Atomaterials, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria 3122, Australia
| | - Alan Kin Tak Lau
- Centre for Translational Atomaterials, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria 3122, Australia
| | - Tianyi Ma
- School of Science, RMIT University, Melbourne, Victoria 3000, Australia.,Centre for Translational Atomaterials, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria 3122, Australia
| | - Cheng-Wei Qiu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore
| | - Baohua Jia
- School of Science, RMIT University, Melbourne, Victoria 3000, Australia.,The Australian Research Council (ARC) Industrial Transformation Training, Centre in Surface Engineering for Advanced Materials (SEAM), Swinburne University of Technology, Hawthorn, Victoria 3122, Australia.,Centre for Translational Atomaterials, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria 3122, Australia
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13
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Jang YJ, Kim JH. Two-dimensional transition metal dichalcogenides as an emerging platform for singlet fission solar cells. Chem Asian J 2022; 17:e202200265. [PMID: 35644937 DOI: 10.1002/asia.202200265] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/25/2022] [Indexed: 11/06/2022]
Abstract
Singlet fission, a rapid exciton doubling process via inverse Auger recombination, is recognized as one of the most practical and feasible means for overcoming the Shockley-Queisser limit. Singlet fission solar cells are generally developed by integrating photon downconversion organic semiconductors into conventional photovoltaic devices to break the maximum photovoltaic response of the host semiconductors by virtue of extra triplet excitons. In this regard, proper matching of two different semiconductors and heterointerface engineering are both crucial for highly efficient singlet fission solar cells. Therefore, the aim of this study is to review the prerequisite conditions for efficient triplet transfer at the heterointerfaces and thus highlight the robust spin and valley degrees of freedom of transition metal dichalcogenides with the ultimate goal of stimulating research into next-generation singlet fission solar cells.
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Affiliation(s)
- Yu Jin Jang
- Sungkyunkwan University, Convergence Research Center for Energy and Environmental Sciences, KOREA, REPUBLIC OF
| | - Ji-Hee Kim
- Sungkyunkwan University, Department of Energy Science, 2066 Seoburo, Jangangu, Suwon, KOREA, REPUBLIC OF
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14
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Costantini R, Cilento F, Salvador F, Morgante A, Giorgi G, Palummo M, Dell’Angela M. Photo-induced lattice distortion in 2H-MoTe2 probed by time-resolved core level photoemission. Faraday Discuss 2022; 236:429-441. [DOI: 10.1039/d1fd00105a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The technological interest in MoTe2 as a phase engineered material is related to the possibility of triggering the 2H-1T’ phase transition by optical excitation, potentially allowing for an accurate patterning...
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15
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Han X, Liang X, He D, Jiao L, Wang Y, Zhao H. Photocarrier Dynamics in MoTe 2 Nanofilms with 2 H and Distorted 1 T Lattice Structures. ACS APPLIED MATERIALS & INTERFACES 2021; 13:44703-44710. [PMID: 34494811 DOI: 10.1021/acsami.1c09698] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Molybdenum telluride (MoTe2), an emerging layered two-dimensional (2D) material, possesses excellent phase-changing properties. Previous studies revealed its reversible transition between 2H and 1T' phases with a transition energy as small as 35 meV. Since 1T'-MoTe2 is metallic, it can serve as an electrical contact for semiconducting 2H-MoTe2-based optoelectronic devices. Here, the photocarrier dynamics in MoTe2 nanofilms synthesized by a one-step method and with coexisting multiple phases are investigated by transient absorption measurements. Both the energy relaxation time and the recombination lifetime of the excitons are shorter in the 1T'-MoTe2 compared to its 2H phase. These results provide information on the different photocarrier dynamical properties of these two phases, which is important for future 2D optoelectronic and phase-change electronic devices based on MoTe2.
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Affiliation(s)
- Xiuxiu Han
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044, China
| | - Xingyao Liang
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Dawei He
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044, China
| | - Liying Jiao
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Yongsheng Wang
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044, China
| | - Hui Zhao
- Department of Physics and Astronomy, The University of Kansas, Lawrence, Kansas 66045, United States
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16
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Marri I, Ossicini S. Multiple exciton generation in isolated and interacting silicon nanocrystals. NANOSCALE 2021; 13:12119-12142. [PMID: 34250528 DOI: 10.1039/d1nr01747k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
An important challenge in the field of renewable energy is the development of novel nanostructured solar cell devices which implement low-dimensional materials to overcome the limits of traditional photovoltaic systems. For optimal energy conversion in photovoltaic devices, one important requirement is that the full energy of the solar spectrum is effectively used. In this context, the possibility of exploiting features and functionalities induced by the reduced dimensionality of the nanocrystalline phase, in particular by the quantum confinement of the electronic density, can lead to a better use of the carrier excess energy and thus to an increment of the thermodynamic conversion efficiency of the system. Carrier multiplication, i.e. the generation of multiple electron-hole pairs after absorption of one single high-energy photon (with energy at least twice the energy gap of the system), can be exploited to maximize cell performance, promoting a net reduction of loss mechanisms. Over the past fifteen years, carrier multiplication has been recorded in a large variety of semiconductor nanocrystals and other nanostructures. Owing to the role of silicon in solar cell applications, the mission of this review is to summarize the progress in this fascinating research field considering carrier multiplication in Si-based low-dimensional systems, in particular Si nanocrystals, both from the experimental and theoretical point of view, with special attention given to the results obtained by ab initio calculations.
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Affiliation(s)
- Ivan Marri
- Department of Sciences and Methods for Engineering, University of Modena e Reggio Emilia, 42122 Reggio Emilia, Italy.
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17
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Kim JS, Tran MD, Kim ST, Yoo D, Oh SH, Kim JH, Lee YH. Escalated Photocurrent with Excitation Energy in Dual-Gated MoTe 2. NANO LETTERS 2021; 21:1976-1981. [PMID: 33591202 DOI: 10.1021/acs.nanolett.0c04410] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Although van der Waals-layered transition metal dichalcogenides from transient absorption spectroscopy have successfully demonstrated an ideal carrier multiplication (CM) performance with an onset of nearly 2Eg, interpretation of the CM effect from the optical approach remains unresolved owing to the complexity of many-body electron-hole pairs. We demonstrate the escalated photocurrent with excitation photon energy by fabricating the dual-gate p-n junction of a MoTe2 film on a transparent substrate. Electrons and holes were efficiently extracted by eliminating the Schottky barriers in the metal contact and minimizing multiple reflections. The photocurrent was elevated proportionately to the excitation photon energy. The boosted quantum efficiency confirms the multiple electron-hole pair generation of >2Eg, consistent with CM results from an optical approach, pushing the solar cell efficiency beyond the Shockley-Queisser limit.
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Affiliation(s)
- Jun Suk Kim
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Department of Energy Science, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Minh Dao Tran
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
| | - Sung Tae Kim
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Department of Energy Science, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Daehan Yoo
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Sang-Hyun Oh
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Ji-Hee Kim
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Department of Energy Science, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Young Hee Lee
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Department of Energy Science, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
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18
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Shin HJ, Bae S, Sim S. Ultrafast Auger process in few-layer PtSe 2. NANOSCALE 2020; 12:22185-22191. [PMID: 33135719 DOI: 10.1039/d0nr05897a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Enhanced many-body interactions due to strong Coulomb interactions and quantum confinement are one of the most prominent features of two-dimensional systems. The Auger process is a representative many-body interaction typically observed in two-dimensional semiconductors, determining important physical properties of materials, such as carrier lifetime, photoconductivity, and emission quantum yield. Recently, platinum dichalcogenides, represented by PtSe2 and PtS2, have attracted great attention due to their superior air stability, thickness-dependent semimetal-to-semiconductor transition, and exotic magnetic characteristics. However, the Auger process in platinum dichalcogenides has not been investigated to date. Here, we utilized ultrafast optical-pump terahertz-probe spectroscopy to explore carrier dynamics in few-layer semiconducting PtSe2. Most of the excited carriers are trapped by defects within ∼10 ps after excitation due to high defect density. We overcome this challenge by raising the excitation intensity to saturate trap sites with carriers, and observed a many-body process involving the carriers that survived the rapid trapping. This process is not band-to-band Auger recombination, but rather defect-assisted Auger recombination in which free carriers interact with trapped carriers at defects. Theoretical simulations show that this three-body Auger process can be approximated as bimolecular recombination at the rate of ∼3.3 × 10-3 cm2 s-1. This work provides insights into the interplay between ultrafast many-body processes and defects in two-dimensional semiconductors.
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Affiliation(s)
- Hee Jun Shin
- Pohang Accelerator Laboratory, POSTECH, Pohang 37673, Korea
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19
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Zhou Q, Zhou H, Tao W, Zheng Y, Chen Y, Zhu H. Highly Efficient Multiple Exciton Generation and Harvesting in Few-Layer Black Phosphorus and Heterostructure. NANO LETTERS 2020; 20:8212-8219. [PMID: 33044075 DOI: 10.1021/acs.nanolett.0c03328] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Multiple exciton generation (MEG) in semiconductors that yields two or more excitons by absorbing one high-energy photon has been proposed to break the Shockley-Queisser limit and boost photon-to-electron conversion efficiency. However, MEG performance in conventional bulk semiconductors or later colloidal nanocrystals is far from satisfactory. Here, we report efficient MEG in few-layer black phosphorus (BP), a direct narrow bandgap two-dimensional (2D) semiconductor with layer-tunable properties. MEG performance improves with decreasing layer number and reaches 2.09Eg threshold and 93% efficiency for two-layer BP, approaching energy conservation limit. The enhanced MEG can be attributed to strong Coulomb interaction and high density of states in 2D materials. Furthermore, MEG of BP shows negligible degradation in vertical heterostructure and multielectron can be extracted by interfacial transfer with near unity yield. These results suggest 2D semiconductors as an ideal system for next generation highly efficient light emission and charge transfer devices.
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Affiliation(s)
- Qiaohui Zhou
- State Key Laboratory of Modern Optical Instrumentation, Centre for Chemistry of High-Performance and Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang China
| | - Hongzhi Zhou
- State Key Laboratory of Modern Optical Instrumentation, Centre for Chemistry of High-Performance and Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang China
| | - Weijian Tao
- State Key Laboratory of Modern Optical Instrumentation, Centre for Chemistry of High-Performance and Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang China
| | - Yizhen Zheng
- State Key Laboratory of Modern Optical Instrumentation, Centre for Chemistry of High-Performance and Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang China
| | - Yuzhong Chen
- State Key Laboratory of Modern Optical Instrumentation, Centre for Chemistry of High-Performance and Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang China
| | - Haiming Zhu
- State Key Laboratory of Modern Optical Instrumentation, Centre for Chemistry of High-Performance and Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang China
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20
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Zheng W, Bonn M, Wang HI. Photoconductivity Multiplication in Semiconducting Few-Layer MoTe 2. NANO LETTERS 2020; 20:5807-5813. [PMID: 32697101 PMCID: PMC7458477 DOI: 10.1021/acs.nanolett.0c01693] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 07/22/2020] [Indexed: 06/11/2023]
Abstract
We report efficient photoconductivity multiplication in few-layer 2H-MoTe2 as a direct consequence of an efficient steplike carrier multiplication with near unity quantum yield and high carrier mobility (∼45 cm2 V-1 s-1) in MoTe2. This photoconductivity multiplication is quantified using ultrafast, excitation-wavelength-dependent photoconductivity measurements employing contact-free terahertz spectroscopy. We discuss the possible origins of efficient carrier multiplication in MoTe2 to guide future theoretical investigations. The combination of photoconductivity multiplication and the advantageous bandgap renders MoTe2 as a promising candidate for efficient optoelectronic devices.
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Affiliation(s)
- Wenhao Zheng
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Mischa Bonn
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Hai I. Wang
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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21
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Maiti S, Ferro S, Poonia D, Ehrler B, Kinge S, Siebbeles LDA. Efficient Carrier Multiplication in Low Band Gap Mixed Sn/Pb Halide Perovskites. J Phys Chem Lett 2020; 11:6146-6149. [PMID: 32672041 PMCID: PMC7416307 DOI: 10.1021/acs.jpclett.0c01788] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 07/16/2020] [Indexed: 05/31/2023]
Abstract
Carrier multiplication (CM) generates multiple electron-hole pairs in a semiconductor from a single absorbed photon with energy exceeding twice the band gap. Thus, CM provides a promising way to circumvent the Shockley-Queisser limit of solar cells. The ideal material for CM should have significant overlap with the solar spectrum and should be able to fully utilize the excess energy above the band gap for additional charge carrier generation. We report efficient CM in mixed Sn/Pb halide perovskites (band gap of 1.28 eV) with onset just above twice the band gap. The CM rate outcompetes the carrier cooling process leading to efficient CM with a quantum yield of 2 for photoexcitation at 2.8 times the band gap. Such efficient CM characteristics add to the many advantageous properties of mixed Sn/Pb metal halide perovskites for photovoltaic applications.
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Affiliation(s)
- Sourav Maiti
- Optoelectronic
Materials Section, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, Delft 2629 HZ, The Netherlands
| | - Silvia Ferro
- Center
for Nanophotonics, AMOLF, Science Park 104, Amsterdam, The Netherlands
| | - Deepika Poonia
- Optoelectronic
Materials Section, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, Delft 2629 HZ, The Netherlands
| | - Bruno Ehrler
- Center
for Nanophotonics, AMOLF, Science Park 104, Amsterdam, The Netherlands
| | - Sachin Kinge
- Optoelectronic
Materials Section, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, Delft 2629 HZ, The Netherlands
- Materials
Research & Development, Toyota Motor
Europe, Hoge Wei 33, B-1913 Zaventem, Belgium
| | - Laurens D. A. Siebbeles
- Optoelectronic
Materials Section, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, Delft 2629 HZ, The Netherlands
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22
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Kim ST, Kim JH, Lee YH. Carrier Multiplication in PbS Quantum Dots Anchored on a Au Tip using Conductive Atomic Force Microscopy. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1908461. [PMID: 32128896 DOI: 10.1002/adma.201908461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 02/12/2020] [Indexed: 06/10/2023]
Abstract
Carrier multiplication (CM) is the amplification of the excited carrier density by two times or more when the incident photon energy is larger than twice the bandgap of semiconductors. A practical approach to demonstrate the CM involves the direct measurement of photocurrent in the device. Specifically, photocurrent measurement in quantum dots (QDs) is typically limited by high contact resistance and long carrier-transfer length, which yields a low CM conversion efficiency and high CM threshold energy. Here, the local photocurrent is measured to evaluate the CM quantum efficiency from a QD-attached Au tip of a conductive atomic force microscope (CAFM) system. The photocurrent is efficiently measured between the PbS QDs anchored on a Au tip and a graphene layer on a SiO2 /Si substrate as a counter electrode, yielding an extremely short channel length that reduces the contact resistance. The quantum efficiency extracted from the local photocurrent data with an incident photon energy exhibits a step-like behavior. More importantly, the CM threshold energy is as low as twice the bandgap, which is the lowest threshold energy of optically observed QDs to date. This enables the CAFM-based photocurrent technique to directly evaluate the CM conversion efficiency in low-dimensional materials.
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Affiliation(s)
- Sung-Tae Kim
- IBS Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science, Suwon, 16419, Korea
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Ji-Hee Kim
- IBS Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science, Suwon, 16419, Korea
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Young Hee Lee
- IBS Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science, Suwon, 16419, Korea
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
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