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Qian Q, Wu W, Peng L, Wang Y, Tan AMZ, Liang L, Hus SM, Wang K, Choudhury TH, Redwing JM, Puretzky AA, Geohegan DB, Hennig RG, Ma X, Huang S. Photoluminescence Induced by Substitutional Nitrogen in Single-Layer Tungsten Disulfide. ACS NANO 2022; 16:7428-7437. [PMID: 35536919 DOI: 10.1021/acsnano.1c09809] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The electronic and optical properties of two-dimensional materials can be strongly influenced by defects, some of which can find significant implementations, such as controllable doping, prolonged valley lifetime, and single-photon emissions. In this work, we demonstrate that defects created by remote N2 plasma exposure in single-layer WS2 can induce a distinct low-energy photoluminescence (PL) peak at 1.59 eV, which is in sharp contrast to that caused by remote Ar plasma. This PL peak has a critical requirement on the N2 plasma exposure dose, which is strongest for WS2 with about 2.0% sulfur deficiencies (including substitutions and vacancies) and vanishes at 5.6% or higher sulfur deficiencies. Both experiments and first-principles calculations suggest that this 1.59 eV PL peak is caused by defects related to the sulfur substitutions by nitrogen, even though low-temperature PL measurements also reveal that not all the sulfur vacancies are remedied by the substitutional nitrogen. The distinct low-energy PL peak suggests that the substitutional nitrogen defect in single-layer WS2 can potentially serve as an isolated artificial atom for creating single-photon emitters, and its intensity can also be used to monitor the doping concentrations of substitutional nitrogen.
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Affiliation(s)
- Qingkai Qian
- Key Laboratory of Optoelectronic Technology and System (Ministry of Education), College of Optoelectronic Engineering, Chongqing University, Chongqing 400044, China
- Department of Electrical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Wenjing Wu
- Department of Electrical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Lintao Peng
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Yuanxi Wang
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Anne Marie Z Tan
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, United States
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Liangbo Liang
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Saban M Hus
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Ke Wang
- Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Tanushree H Choudhury
- 2D Crystal Consortium, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Joan M Redwing
- 2D Crystal Consortium, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Alexander A Puretzky
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - David B Geohegan
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Richard G Hennig
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Xuedan Ma
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Shengxi Huang
- Department of Electrical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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Zhai BG, Xu H, Zhang Q, Huang YM. Blue Photoluminescence and Cyan-Colored Afterglow of Undoped SrSO 4 Nanoplates. ACS OMEGA 2021; 6:10129-10140. [PMID: 34056167 PMCID: PMC8153658 DOI: 10.1021/acsomega.1c00194] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 03/31/2021] [Indexed: 06/12/2023]
Abstract
Undoped SrSO4 nanoplates were synthesized via the composite hydroxide-mediated approach. The products were characterized by means of X-ray diffractometry, scanning electron microscopy, X-ray energy-dispersive spectroscopy, X-ray photoelectron spectroscopy, photoluminescence (PL) spectroscopy, electron spin resonance technique, afterglow spectroscopy, and thermoluminescence dosimetry. The steady-state PL spectrum of undoped SrSO4 nanoplates can be deconvoluted into two distinct Gaussian bands centered at 2.97 eV (417.2 nm) and 2.56 eV (484.4 nm), respectively. The nature of the defect emissions is confirmed through the emission-wavelength-dependent PL decays as well as the excitation-wavelength-dependent PL decays. A cyan-colored afterglow from undoped SrSO4 nanoplates can be observed with naked eyes in the dark, and the afterglow spectrum of the undoped SrSO4 nanoplates exhibits a peak at about 492 nm (2.52 eV). The duration of the afterglow is measured to be 16 s. The thermoluminescence glow curve of the undoped SrSO4 nanoplates shows a peak at about 40.1 °C. The trapping parameters are determined with the peak shape method, the calculated value of the trap depth is 0.918 eV, and the frequency factor is 1.2 × 1014 s-1. Using density functional calculations, the band structures and densities of states of oxygen-deficient SrSO4 and strontium-deficient SrSO4 are presented. The mechanisms of the cyan-colored afterglow are discussed for undoped SrSO4, and the oxygen vacancies in SrSO4 are proposed to be the luminescence center of the afterglow.
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Affiliation(s)
- Bao-gai Zhai
- School of Microelectronics and Control
Engineering, Changzhou University, Changzhou 213164, China
| | - Hanfei Xu
- School of Microelectronics and Control
Engineering, Changzhou University, Changzhou 213164, China
| | - Qing Zhang
- School of Microelectronics and Control
Engineering, Changzhou University, Changzhou 213164, China
| | - Yuan Ming Huang
- School of Microelectronics and Control
Engineering, Changzhou University, Changzhou 213164, China
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Hwang J, Zhang C, Kim YS, Wallace RM, Cho K. Giant renormalization of dopant impurity levels in 2D semiconductor MoS 2. Sci Rep 2020; 10:4938. [PMID: 32188874 PMCID: PMC7080777 DOI: 10.1038/s41598-020-61675-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Accepted: 01/14/2020] [Indexed: 11/09/2022] Open
Abstract
Substitutional doping in 2D semiconductor MoS2 was investigated by charge transition level (CTL) calculations for Nitrogen group (N, P, As, Sb) and Halogen group (F, Cl, Br, I) dopants at the S site of monolayer MoS2. Both n-type and p-type dopant levels are calculated to be deep mid-gap states (~1 eV from band edges) from DFT total energy-based CTL and separate DFT + GW calculations. The deep dopant levels result from the giant renormalization of hydrogen-like defect states by reduced dielectric screening in ultrathin 2D films. Theoretical analysis based on Keldysh formulation provides a consistent impurity binding energy of ~1 eV for dielectric thin films. These findings of intrinsic deep impurity levels in 2D semiconductors MoS2 may be applicable to diverse novel emerging device applications.
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Affiliation(s)
- Jeongwoon Hwang
- Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas, 75080, USA
- Department of Physics Education, Chonnam National University, Gwangju, 61186, Korea
| | - Chenxi Zhang
- Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas, 75080, USA
| | - Yong-Sung Kim
- Korea Research Institute of Standards and Science, Yuseong, Daejeon, 305-340, Korea
| | - Robert M Wallace
- Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas, 75080, USA
| | - Kyeongjae Cho
- Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas, 75080, USA.
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Golze D, Dvorak M, Rinke P. The GW Compendium: A Practical Guide to Theoretical Photoemission Spectroscopy. Front Chem 2019; 7:377. [PMID: 31355177 PMCID: PMC6633269 DOI: 10.3389/fchem.2019.00377] [Citation(s) in RCA: 153] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 05/08/2019] [Indexed: 12/22/2022] Open
Abstract
The GW approximation in electronic structure theory has become a widespread tool for predicting electronic excitations in chemical compounds and materials. In the realm of theoretical spectroscopy, the GW method provides access to charged excitations as measured in direct or inverse photoemission spectroscopy. The number of GW calculations in the past two decades has exploded with increased computing power and modern codes. The success of GW can be attributed to many factors: favorable scaling with respect to system size, a formal interpretation for charged excitation energies, the importance of dynamical screening in real systems, and its practical combination with other theories. In this review, we provide an overview of these formal and practical considerations. We expand, in detail, on the choices presented to the scientist performing GW calculations for the first time. We also give an introduction to the many-body theory behind GW, a review of modern applications like molecules and surfaces, and a perspective on methods which go beyond conventional GW calculations. This review addresses chemists, physicists and material scientists with an interest in theoretical spectroscopy. It is intended for newcomers to GW calculations but can also serve as an alternative perspective for experts and an up-to-date source of computational techniques.
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Affiliation(s)
- Dorothea Golze
- Department of Applied Physics, Aalto University, School of Science, Espoo, Finland
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Linderälv C, Lindman A, Erhart P. A Unifying Perspective on Oxygen Vacancies in Wide Band Gap Oxides. J Phys Chem Lett 2018; 9:222-228. [PMID: 29265821 DOI: 10.1021/acs.jpclett.7b03028] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Wide band gap oxides are versatile materials with numerous applications in research and technology. Many properties of these materials are intimately related to defects, with the most important defect being the oxygen vacancy. Here, using electronic structure calculations, we show that the charge transition level (CTL) and eigenstates associated with oxygen vacancies, which to a large extent determine their electronic properties, are confined to a rather narrow energy range, even while band gap and the electronic structure of the conduction band vary substantially. Vacancies are classified according to their character (deep versus shallow), which shows that the alignment of electronic eigenenergies and CTL can be understood in terms of the transition between cavity-like localized levels in the large band gap limit and strong coupling between conduction band and vacancy states for small to medium band gaps. We consider both conventional and hybrid functionals and demonstrate that the former yields results in very good agreement with the latter provided that band edge alignment is taken into account.
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Affiliation(s)
| | - Anders Lindman
- Chalmers University of Technology , Department of Physics, Gothenburg, Sweden
| | - Paul Erhart
- Chalmers University of Technology , Department of Physics, Gothenburg, Sweden
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