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Oh JS, Jo KJ, Kang MC, An BS, Kwon Y, Lim HW, Cho MH, Baik H, Yang CW. Measurement of dielectric function and bandgap of germanium telluride using monochromated electron energy-loss spectroscopy. Micron 2023; 172:103487. [PMID: 37285687 DOI: 10.1016/j.micron.2023.103487] [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: 03/27/2023] [Revised: 05/16/2023] [Accepted: 05/30/2023] [Indexed: 06/09/2023]
Abstract
Using a monochromator in transmission electron microscopy, a low-energy-loss spectrum can provide inter- and intra-band transition information for nanoscale devices with high energy and spatial resolutions. However, some losses, such as Cherenkov radiation, phonon scattering, and surface plasmon resonance superimposed at zero-loss peak, make it asymmetric. These pose limitations to the direct interpretation of optical properties, such as complex dielectric function and bandgap onset in the raw electron energy-loss spectra. This study demonstrates measuring the dielectric function of germanium telluride using an off-axis electron energy-loss spectroscopy method. The interband transition from the measured complex dielectric function agrees with the calculated band structure of germanium telluride. In addition, we compare the zero-loss subtraction models and propose a reliable routine for bandgap measurement from raw valence electron energy-loss spectra. Using the proposed method, the direct bandgap of germanium telluride thin film was measured from the low-energy-loss spectrum in transmission electron microscopy. The result is in good agreement with the bandgap energy measured using an optical method.
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Affiliation(s)
- Jin-Su Oh
- School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, the Republic of Korea
| | - Kyu-Jin Jo
- School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, the Republic of Korea
| | - Min-Chul Kang
- School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, the Republic of Korea
| | - Byeong-Seon An
- School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, the Republic of Korea
| | - Yena Kwon
- School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, the Republic of Korea
| | - Hyeon-Wook Lim
- Department of Physics, Yonsei University, Seoul 03722, the Republic of Korea
| | - Mann-Ho Cho
- Department of Physics, Yonsei University, Seoul 03722, the Republic of Korea
| | - Hionsuck Baik
- Seoul Center, Korea Basic Science Institute (KBSI), Seoul 02841, the Republic of Korea
| | - Cheol-Woong Yang
- School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, the Republic of Korea.
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Yan X, Jin Q, Jiang Y, Yao T, Li X, Tao A, Gao C, Chen C, Ma X, Ye H. Direct Determination of Band Gap of Defects in a Wide Band Gap Semiconductor. ACS APPLIED MATERIALS & INTERFACES 2022; 14:36875-36881. [PMID: 35926161 DOI: 10.1021/acsami.2c10143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Crystal defects play an important role in the degradation and failure of semiconductor materials and devices. Direct determination of band gap of defects is a critical step for clarifying how the defects affect the physical properties of semiconductors. Here, high-quality aluminum nitride (AlN) thin films were grown epitaxially on single-crystal Al2O3 substrates via pulsed laser deposition. The atomic structure and band gap of three types of inversion domain boundaries (IDBs) in AlN were determined using aberration-corrected transmission electron microscopy and atomic-resolution valence electron energy-loss spectroscopy. It was found that the band gap of all of the IDBs reduces evidently compared to that of the bulk AlN. The maximum band gap reduction of the IDBs is 1.0 eV. First-principles calculations revealed that the band gap reduction of the IDBs is mainly due to the rise of pz orbital at the valence band maximum, which originates from the elongated Al-N bonds along the [0001] direction at the IDBs. The successful band gap determination of defects paves an avenue for quantitatively evaluating the effect of defects on the performance of semiconductor materials and devices.
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Affiliation(s)
- Xuexi Yan
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, School of Material Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
- Jihua Lab, Foshan 528251, China
| | - Qianqian Jin
- School of Microelectronics and Materials Engineering, Guangxi University of Science and Technology, Liuzhou 545006, China
| | - Yixiao Jiang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, School of Material Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
- Jihua Lab, Foshan 528251, China
| | - Tingting Yao
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, School of Material Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
- Jihua Lab, Foshan 528251, China
| | - Xiang Li
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, School of Material Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
- Jihua Lab, Foshan 528251, China
| | - Ang Tao
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, School of Material Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
- Jihua Lab, Foshan 528251, China
| | - Chunyang Gao
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, School of Material Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
- Jihua Lab, Foshan 528251, China
| | - Chunlin Chen
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, School of Material Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
- Jihua Lab, Foshan 528251, China
| | - Xiuliang Ma
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, School of Material Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
- State Key Lab of Advanced Processing and Recycling on Non-Ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China
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Wang YY, Jin Q, Zhuang K, Choi JK, Nxumalo J. Band gap measurement by nano-beam STEM with small off-axis angle transmission electron energy loss spectroscopy (TEELS). Ultramicroscopy 2020; 220:113164. [PMID: 33186852 DOI: 10.1016/j.ultramic.2020.113164] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 10/24/2020] [Accepted: 11/01/2020] [Indexed: 11/28/2022]
Abstract
An energy band gap measurement method based on nano-beam STEM with small off-axis angle valence band transmission electron energy loss spectroscopy (TEELS) is reported. The effect of multiple scattering event is removed by self-convolution method to obtain a single scattering loss function and a dielectric function is calculated from the single scattering valence band energy loss function through Kramers-Kronig (K-K) analysis. Optical band gaps are extracted from energy loss spectra and the imaginary part of the dielectric functions for crystalline and amorphous SiOx, SiNx, and SiON through linear fitting of on-set regions yielding results that are independent of sample thickness. The TEELS band gap data are consistent with those obtained from reflection electron energy loss spectroscopy (REELS) measurements.
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Affiliation(s)
- Yun-Yu Wang
- Micron Technology, 8000 S. Federal Way, Boise, ID 83716, USA.
| | - Qiang Jin
- Micron Technology, 8000 S. Federal Way, Boise, ID 83716, USA
| | - Kent Zhuang
- Micron Technology, 8000 S. Federal Way, Boise, ID 83716, USA
| | - Jae Kyu Choi
- Micron Technology, 8000 S. Federal Way, Boise, ID 83716, USA
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Guzzinati G, Altantzis T, Batuk M, De Backer A, Lumbeeck G, Samaee V, Batuk D, Idrissi H, Hadermann J, Van Aert S, Schryvers D, Verbeeck J, Bals S. Recent Advances in Transmission Electron Microscopy for Materials Science at the EMAT Lab of the University of Antwerp. MATERIALS (BASEL, SWITZERLAND) 2018; 11:E1304. [PMID: 30060556 PMCID: PMC6117696 DOI: 10.3390/ma11081304] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 07/25/2018] [Accepted: 07/26/2018] [Indexed: 01/13/2023]
Abstract
The rapid progress in materials science that enables the design of materials down to the nanoscale also demands characterization techniques able to analyze the materials down to the same scale, such as transmission electron microscopy. As Belgium's foremost electron microscopy group, among the largest in the world, EMAT is continuously contributing to the development of TEM techniques, such as high-resolution imaging, diffraction, electron tomography, and spectroscopies, with an emphasis on quantification and reproducibility, as well as employing TEM methodology at the highest level to solve real-world materials science problems. The lab's recent contributions are presented here together with specific case studies in order to highlight the usefulness of TEM to the advancement of materials science.
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Affiliation(s)
- Giulio Guzzinati
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
| | - Thomas Altantzis
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
| | - Maria Batuk
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
| | - Annick De Backer
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
| | - Gunnar Lumbeeck
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
| | - Vahid Samaee
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
| | - Dmitry Batuk
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
| | - Hosni Idrissi
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
- Institute of Mechanics, Materials and Civil Engineering, Université catholique de Louvain, Louvain-la-Neuve 1348, Belgium.
| | - Joke Hadermann
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
| | - Sandra Van Aert
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
| | | | - Johan Verbeeck
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
| | - Sara Bals
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
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