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Xing S, Wang M, Wang Y, Tao H, Cui Y, Liu S, He M, Song B, Jian J, Tian X, Zhang Z. Electron energy loss spectroscopy and first-principles study of GaN via Zn doping. Micron 2021; 143:103012. [PMID: 33524916 DOI: 10.1016/j.micron.2021.103012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 01/09/2021] [Accepted: 01/09/2021] [Indexed: 11/26/2022]
Abstract
The electronic structure of GaN and GaN:Zn was investigated by electron energy loss spectroscopy and first-principles calculations. In the low-loss spectrum, the interband transitions are assigned to the observed energy loss peaks. After Zn doping, impurity levels are introduced to the density of states and hybrid orbitals of N 2p and Zn 3d are formed around the Fermi level. In the nitrogen K-edge, an additional peak was observed due to the formation of donor defect states. A core-hole effect is believed to be significant for simulation of the N K-edge for both GaN and GaN:Zn.
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Affiliation(s)
- Shuang Xing
- School of Materials Science and Engineering, Dalian Jiaotong University, Dalian, 116028, PR China
| | - Manfu Wang
- School of Materials Science and Engineering, Dalian Jiaotong University, Dalian, 116028, PR China
| | - Yaru Wang
- School of Materials Science and Engineering, Dalian Jiaotong University, Dalian, 116028, PR China
| | - Hualong Tao
- School of Materials Science and Engineering, Dalian Jiaotong University, Dalian, 116028, PR China
| | - Yan Cui
- School of Materials Science and Engineering, Dalian Jiaotong University, Dalian, 116028, PR China
| | - Shimin Liu
- School of Materials Science and Engineering, Dalian Jiaotong University, Dalian, 116028, PR China
| | - Ming He
- School of Physics and Materials Engineering, Dalian Minzu University, Dalian, 116600, PR China.
| | - Bo Song
- Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin, 150080, PR China
| | - Jikang Jian
- School of Physics and Optoelectronic Engineering, Guangdong University of Technology, Guangdong, 510006, PR China
| | - Xingjian Tian
- School of Materials Science and Engineering, Dalian Jiaotong University, Dalian, 116028, PR China
| | - Zhihua Zhang
- School of Materials Science and Engineering, Dalian Jiaotong University, Dalian, 116028, PR China.
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Grad GB, Bonzi EV. Analysis of X-ray absorption spectra of the K and L2,3 edges of GaN within the FP-LAPW method. Appl Radiat Isot 2016; 110:244-250. [PMID: 26861041 DOI: 10.1016/j.apradiso.2016.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Revised: 01/18/2016] [Accepted: 02/02/2016] [Indexed: 10/22/2022]
Abstract
Gallium nitride, GaN, is a semiconductor material with several technological applications. In this work we obtain ab initio XANES spectra using FP-LAPW method within the DFT formalism using different potentials (LDA, PBE and TB-mBJ) in order to study the electronic properties of the system. The spectra calculated using the effect of the fractional core hole were compared with experimental data obtaining a very good agreement.
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The Application of Scanning Transmission Electron Microscopy (STEM) to the Study of Nanoscale Systems. MODELING NANOSCALE IMAGING IN ELECTRON MICROSCOPY 2012. [DOI: 10.1007/978-1-4614-2191-7_2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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Electron energy loss near edge structure (ELNES) spectra of AlN and AlGaN: A theoretical study using the Wien2k and Telnes programs. Micron 2008; 39:690-7. [DOI: 10.1016/j.micron.2007.10.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Abstract
The Wien2k code is widely used for the calculation of electron energy loss spectra. Low loss spectra can be calculated with the OPTIC package while core loss spectra are calculated with the TELNES program. A new version, TELNES.2, takes into account the effects of relativity for anisotropic materials. In this paper we discuss the effects of different parameters used for the self-consistent calculation of the electron density on the obtained spectra. We give an overview of possibilities for the calculation of complicated systems requiring a super-cell, like defects or disordered systems. We discuss the problem of the core hole and of the calculation of orientation-sensitive spectra and give an overview of results already published.
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Affiliation(s)
- C Hébert
- Institut für Festkörperphysik, Technische Universität Wien, A-1040 Wien, Austria.
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Mizoguchi T, Tatsumi K, Tanaka I. Peak assignments of ELNES and XANES using overlap population diagrams. Ultramicroscopy 2006; 106:1120-8. [PMID: 16870343 DOI: 10.1016/j.ultramic.2006.04.027] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Revised: 12/15/2005] [Accepted: 04/06/2006] [Indexed: 10/24/2022]
Abstract
The usefulness of overlap population (OP) diagrams for peak assignments of an electron energy loss near-edge structure (ELNES) and an X-ray absorption near-edge structure (XANES) is demonstrated. Mg-K, L(2,3), and O-K edges of MgO are taken as examples. Theoretical calculations are performed using a first-principles orthogonalized linear combination of atomic orbitals (OLCAO) method. A core-hole is included explicitly, and a large supercell is used to minimize artificial interactions among the core-holes in adjacent cells. All experimental spectra are quantitatively reproduced by the calculations. The OP diagrams for a selected pair of atomic orbitals are computed in order to provide proper assignments for each peak in ELNES and XANES. They are interpreted in terms of interactions among Mg-Mg and Mg-O bonds. Results are found to be consistent to our previous conclusion, which was obtained using a cluster method [T. Mizoguchi, et al., Phys. Rev. B 61 (2000) 2180]. The powerful combination of the OP diagram and a high-energy resolution ELNES to obtain fine electronic structures is also demonstrated.
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Affiliation(s)
- Teruyasu Mizoguchi
- National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, One Cyclotron Road, MS 72-105, Berkeley, CA 94720, USA.
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Lazar S, Botton GA, Zandbergen HW. Enhancement of resolution in core-loss and low-loss spectroscopy in a monochromated microscope. Ultramicroscopy 2006; 106:1091-103. [PMID: 16872750 DOI: 10.1016/j.ultramic.2006.04.024] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2005] [Revised: 11/23/2005] [Accepted: 04/06/2006] [Indexed: 11/25/2022]
Abstract
The significant enhancement of the energy resolution in the new generation of commercially available monochromated transmission electron microscopes presents new challenges in term of selecting the correct experimental conditions and understanding the various effects that can potentially influence the quality of the EELS data. In this respect we investigated the effect of point spread function of the detector and spectrum-diffraction mixing on the energy resolution and the intensity of the zero loss peak tails. Alternative approaches to improve the energy resolution by mathematical methods have been tested. By using a simple and commonly available test case (Si L(2,3) edges) we assessed the efficiency of the deconvolution algorithms to improve the resolution. The results show that the deconvolution is not always successful in improving the resolution of the core loss EELS data and the results may not always be reliable. Contrary to this, the application of the Richardson-Lucy deconvolution algorithm on some bandgap measurements data appears to be very effective. The procedure proved successful in removing the contribution of the zero-loss peak tails and allows an easier access to spectroscopic information starting at energy losses as low as of 0.5 eV with monochromated spectra and 1 eV with the non-monochromated spectra.
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Affiliation(s)
- S Lazar
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628CJ Delft, The Netherlands.
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Moreno MS, Jorissen K, Rehr JJ. Practical aspects of electron energy-loss spectroscopy (EELS) calculations using FEFF8. Micron 2006; 38:1-11. [PMID: 16714118 DOI: 10.1016/j.micron.2006.03.011] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We discuss the application of the ab initio program FEFF8 to calculations of electron energy-loss spectroscopy (EELS), focusing in particular on core-loss spectra. FEFF8 is based on a self-consistent, real space multiple scattering formalism. We focus on issues relevant to practical simulations, including the construction of well-converged potentials, the treatment of inelastic losses and exchange-correlation potentials and the core-hole. We also discuss how to account for experimental conditions, for example, sample orientation and finite temperature effects such as Debye-Waller factors. Finally we discuss the interpretation of the spectra in terms of electronic structure and local projected density of states (LDOS). As an explicit example, we illustrate various features of the code by application to the ionization edges of GaN.
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Affiliation(s)
- M S Moreno
- Centro Atómico Bariloche, Materials Department, 8400 San Carlos de Bariloche, Argentina.
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Mizoguchi T, Buban JP, Matsunaga K, Yamamoto T, Ikuhara Y. First-principles study on incidence direction, individual site character, and atomic projection dependences of ELNES for perovskite compounds. Ultramicroscopy 2006; 106:92-104. [PMID: 16043296 DOI: 10.1016/j.ultramic.2005.06.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2004] [Revised: 05/08/2005] [Accepted: 06/10/2005] [Indexed: 11/28/2022]
Abstract
The incidence direction dependence, the individual site character dependence, and the atomic projection dependence of O-K near edge fine structure of the EEL spectrum (ELNES) from YBa2Cu3O7 (YBCO) and SrTiO3 were theoretically simulated using the first-principles band structure calculation. In order to calculate ELNES, a core-hole was introduced at the oxygen 1s orbital, and sufficiently large supercells composed of more than 100 atoms were employed. We found that the intensity of the first peak of O-K ELNES from YBCO strongly depends on the atomic projection direction, and disappears when the spectrum is measured with the other projection directions. The large projection dependence was also predicted in the O-K ELNES of SrTiO3. It was found that those spectral changes according to the position of the projection are caused by the unidirectional Ti-O-Ti bond in SrTiO3.
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Affiliation(s)
- Teruyasu Mizoguchi
- Institute of Engineering Innovation, The University of Tokyo, 2-11-16, Yayoi, Bunkyo, Tokyo 116-0013, Japan.
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