1
|
Meng Z, Shi Z, Feng H, Zhang H, Ren Z, Du Y, Cheng F, Ge B, Cai W, Hao W. Abnormal Relaxation Behavior of Excited Electrons in the Flat Band of Kagome Compound Nb 3Cl 8. ACS APPLIED MATERIALS & INTERFACES 2024. [PMID: 39385456 DOI: 10.1021/acsami.4c12665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/12/2024]
Abstract
Carrier dynamics is crucial in semiconductors, and it determines their conductivity, response time, and overall functionality. In flat bands (FBs), carriers with high effective masses are predicted to host unconventional transport properties. The FBs usually overlap with other trivial energy bands, however, making it difficult to accurately distinguish their carrier dynamics. In this paper, we have investigated the flat-band carrier dynamics of excited electrons in Nb3Cl8, which hosts ideal nonoverlapping FBs near the Fermi level. The optical transition between Hubbard bands is abnormally weakened, exhibiting weak interband absorption and its related slow photoresponse with a time constant of ∼120 s, which are associated with flat-band Mottness-induced large electron effective mass and parity-forbidden transitions. Besides, the localized states created by chlorine vacancies also act as trapping centers for carriers with a time constant of ∼600 s, which are similar to those of the compact localized states of the FB, making the relaxation behavior even more extraordinary. The presence and impacts of atomic defects are confirmed experimentally and theoretically. This work has revealed the abnormal flat-band carrier dynamics of Nb3Cl8, which is essential for understanding the optical, electrical, and thermal transport properties of flat-band materials.
Collapse
Affiliation(s)
- Ziyuan Meng
- School of Physics, Beihang University, Beijing 100191, P. R. China
- Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing 100191, P. R. China
| | - Zhijian Shi
- School of Physics, Beihang University, Beijing 100191, P. R. China
- Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing 100191, P. R. China
| | - Haifeng Feng
- School of Physics, Beihang University, Beijing 100191, P. R. China
- Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing 100191, P. R. China
| | - Hongrun Zhang
- School of Physics, Beihang University, Beijing 100191, P. R. China
- Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing 100191, P. R. China
| | - Zhaoying Ren
- School of Physics, Beihang University, Beijing 100191, P. R. China
- Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing 100191, P. R. China
| | - Yi Du
- School of Physics, Beihang University, Beijing 100191, P. R. China
- Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing 100191, P. R. China
| | - Feng Cheng
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, P. R. China
| | - Binghui Ge
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, P. R. China
| | - Wei Cai
- School of Physics, Beihang University, Beijing 100191, P. R. China
| | - Weichang Hao
- School of Physics, Beihang University, Beijing 100191, P. R. China
- Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing 100191, P. R. China
| |
Collapse
|
2
|
Ji YH, Gao Q, Huang AP, Yang MQ, Liu YQ, Geng XL, Zhang JJ, Wang RZ, Wang M, Xiao ZS, Chu PK. GaO x@GaN Nanowire Arrays on Flexible Graphite Paper with Tunable Persistent Photoconductivity. ACS APPLIED MATERIALS & INTERFACES 2021; 13:41916-41925. [PMID: 34448583 DOI: 10.1021/acsami.1c13355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Flexible optoelectronic synaptic devices that functionally imitate the neural behavior with tunable optoelectronic characteristics are crucial to the development of advanced bioinspired neural networks. In this work, amorphous oxide-decorated GaN nanowire arrays (GaOx@GaN NWAs) are prepared on flexible graphite paper. A GaOx@GaN NWA-based flexible device has tunable persistent photoconductivity (PPC) and shows a conversible fast/slow decay process (SDP). Photoconductivity can be modulated by single or double light pulses with different illumination powers and biases. PPC gives rise to the high-performance SDP such as a long decay time of 2.3 × 105 s. The modulation mechanism is proposed and discussed. Our results reveal an innovative and efficient strategy to produce decorated NWAs on a flexible substrate with tunable optoelectronic properties and exhibit potential for flexible neuromorphic system applications.
Collapse
Affiliation(s)
- Yu-Hang Ji
- School of Physics, Beihang University, Beijing 100191, China
| | - Qin Gao
- School of Physics, Beihang University, Beijing 100191, China
| | - An-Ping Huang
- School of Physics, Beihang University, Beijing 100191, China
| | - Meng-Qi Yang
- Institute of New Energy Materials and Devices, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China
| | - Yan-Qi Liu
- Institute of Laser Engineering, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 999077, China
| | - Xue-Li Geng
- School of Physics, Beihang University, Beijing 100191, China
| | - Jing-Jing Zhang
- School of Physics, Beihang University, Beijing 100191, China
| | - Ru-Zhi Wang
- Institute of New Energy Materials and Devices, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China
| | - Mei Wang
- School of Physics, Beihang University, Beijing 100191, China
| | - Zhi-Song Xiao
- School of Physics, Beihang University, Beijing 100191, China
| | - Paul K Chu
- Department of Physics, Department of Materials Science and Engineering, and Department of Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon 518057, Hong Kong, China
| |
Collapse
|
3
|
Huang X, Zhuo Z, Yan L, Wang Y, Xu N, Song HZ, Zhou L. Single-Layer Zirconium Dihalides ZrX 2 (X = Cl, Br, and I) with Abnormal Ferroelastic Behavior and Strong Anisotropic Light Absorption Ability. J Phys Chem Lett 2021; 12:7726-7732. [PMID: 34355906 DOI: 10.1021/acs.jpclett.1c01958] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Recently, two-dimensional (2D) metal halides have brought out an intensive interest for their unique mechanical, electronic, magnetic, and topological properties. Here, we theoretically report the existence of the single-layer (SL) zirconium dihalide materials ZrX2 (X = Cl, Br, and I) using first-principles calculations. SL ZrX2, which can be obtained from its bulk phase through simple mechanical exfoliation, shows the dynamic, thermodynamic, and mechanical stability. Halogen atoms can effectively tune the electronic structure, dipole moment transition, band alignment, and light absorption. Specifically, ZrX2 monolayers intrinsically exhibit a ferroelasticity with an abnormal 120° orientation rotation, possessing a moderate switching barrier of 24-39 meV/atom. Importantly, we observe superior anisotropic light absorption responses on SL ZrX2 in the visible region. Besides, a series of ZrX2-based excitonic solar cells have been proposed, which hold a large power conversion efficiency limit of 12.4-18.7%.
Collapse
Affiliation(s)
- Xingyong Huang
- Yangtze Delta Region Institute (Huzhou), University of Electronic Science and Technology of China, Huzhou, Zhejiang 313001, China
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China
- Department of Science, Yibin University, Yibin, Sichuan 644007, China
- Southwest Institute of Technical Physics, Chengdu, Sichuan 610054, China
| | - Zhiwen Zhuo
- Hefei National Laboratory of Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Luo Yan
- Yangtze Delta Region Institute (Huzhou), University of Electronic Science and Technology of China, Huzhou, Zhejiang 313001, China
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China
| | - You Wang
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China
- Southwest Institute of Technical Physics, Chengdu, Sichuan 610054, China
| | - Nan Xu
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China
| | - Hai-Zhi Song
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China
- Southwest Institute of Technical Physics, Chengdu, Sichuan 610054, China
| | - Liujiang Zhou
- Yangtze Delta Region Institute (Huzhou), University of Electronic Science and Technology of China, Huzhou, Zhejiang 313001, China
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, China
| |
Collapse
|
4
|
Huang X, Yan L, Zhou Y, Wang Y, Song HZ, Zhou L. Group 11 Transition-Metal Halide Monolayers: High Promises for Photocatalysis and Quantum Cutting. J Phys Chem Lett 2021; 12:525-531. [PMID: 33377387 DOI: 10.1021/acs.jpclett.0c03138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Recently, two-dimensional (2D) metal halides have triggered an enormous interest for their tunable mechanical, electronic, magnetic, and topological properties, greatly enriching the family of 2D materials. Here, based on first-principles calculations, we report a systematic study of group 11 transition-metal halide MX (M = Cu, Ag, Au; X = Cl, Br, I) monolayers. Among them, CuBr, CuI, AgBr, and AgI monolayers exhibit high thermodynamic, dynamic, and mechanic stability. The four stable monolayers have a direct band gap of ∼3.12-3.36 eV and possess high carrier mobility (∼103 cm2 V-1 s-1), suggestive of future photocatalysts for water splitting applications. What is more, the simulations of optical properties confirm that the stable MX monolayers hold the potential for further applications in ultraviolet optical devices and quantum cutting solar materials.
Collapse
Affiliation(s)
- Xingyong Huang
- Southwest Institute of Technical Physics, Chengdu 610054, China
- Faculty of Science, Yibin University, Yibin 644007, China
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Luo Yan
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Yong Zhou
- Southwest Institute of Technical Physics, Chengdu 610054, China
| | - You Wang
- Southwest Institute of Technical Physics, Chengdu 610054, China
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Hai-Zhi Song
- Southwest Institute of Technical Physics, Chengdu 610054, China
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Liujiang Zhou
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, China
| |
Collapse
|