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Ohtake A, Suga T, Goto S, Nakagawa D, Nakamura J. Atomic structure of the Se-passivated GaAs(001) surface revisited. Sci Rep 2023; 13:18140. [PMID: 37875507 PMCID: PMC10598220 DOI: 10.1038/s41598-023-45142-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 10/16/2023] [Indexed: 10/26/2023] Open
Abstract
We present a combined experimental and theoretical study of the Se-treated GaAs(001)-([Formula: see text]) surface. The ([Formula: see text]) structure with the two-fold coordinated Se atom at the outermost layer and the three-fold coordinated Se atom at the third layer was found to be energetically stable and agrees well with the experimental data from scanning tunneling microscopy, low energy electron diffraction, and x-ray photoelectron spectroscopy. This atomic geometry accounts for the improved stability of the Se-treated surface against the oxidation. The present result allows us to address a long-standing question on the structure of the Se-passivated GaAs surface, and will leads us to a more complete understanding of the physical origin of the electrical and chemical passivation of Se-treated GaAs surface.
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Affiliation(s)
- Akihiro Ohtake
- National Institute for Materials Science (NIMS), Tsukuba, 305-0044, Japan.
| | - Takayuki Suga
- Department of Engineering Science, The University of Electro-Communications (UEC-Tokyo), Chofu, Tokyo, 182-8585, Japan
| | - Shunji Goto
- Department of Engineering Science, The University of Electro-Communications (UEC-Tokyo), Chofu, Tokyo, 182-8585, Japan
| | - Daisuke Nakagawa
- Department of Engineering Science, The University of Electro-Communications (UEC-Tokyo), Chofu, Tokyo, 182-8585, Japan
| | - Jun Nakamura
- Department of Engineering Science, The University of Electro-Communications (UEC-Tokyo), Chofu, Tokyo, 182-8585, Japan
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Shang X, Su X, Liu H, Hao H, Li S, Dai D, Li M, Yu Y, Zhang Y, Wang G, Xu Y, Ni H, Niu Z. Annealing-Modulated Surface Reconstruction for Self-Assembly of High-Density Uniform InAs/GaAs Quantum Dots on Large Wafers Substrate. Nanomaterials (Basel) 2023; 13:1959. [PMID: 37446475 DOI: 10.3390/nano13131959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 06/20/2023] [Accepted: 06/21/2023] [Indexed: 07/15/2023]
Abstract
In this work, we developed pre-grown annealing to form β2 reconstruction sites among β or α (2 × 4) reconstruction phase to promote nucleation for high-density, size/wafer-uniform, photoluminescence (PL)-optimal InAs quantum dot (QD) growth on a large GaAs wafer. Using this, the QD density reached 580 (860) μm-2 at a room-temperature (T) spectral FWHM of 34 (41) meV at the wafer center (and surrounding) (high-rate low-T growth). The smallest FWHM reached 23.6 (24.9) meV at a density of 190 (260) μm-2 (low-rate high-T). The mediate rate formed uniform QDs in the traditional β phase, at a density of 320 (400) μm-2 and a spectral FWHM of 28 (34) meV, while size-diverse QDs formed in β2 at a spectral FWHM of 92 (68) meV and a density of 370 (440) μm-2. From atomic-force-microscope QD height distribution and T-dependent PL spectroscopy, it is found that compared to the dense QDs grown in β phase (mediate rate, 320 μm-2) with the most large dots (240 μm-2), the dense QDs grown in β2 phase (580 μm-2) show many small dots with inter-dot coupling in favor of unsaturated filling and high injection to large dots for PL. The controllable annealing (T, duration) forms β2 or β2-mixed α or β phase in favor of a wafer-uniform dot island and the faster T change enables optimal T for QD growth.
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Affiliation(s)
- Xiangjun Shang
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiangbin Su
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hanqing Liu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Huiming Hao
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shulun Li
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Deyan Dai
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Mifeng Li
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Ying Yu
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, China
| | - Yu Zhang
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guowei Wang
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yingqiang Xu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Haiqiao Ni
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Zhichuan Niu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
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Hong M, Cheng CK, Lin YH, Young LB, Cai RF, Hsu CH, Wu CT, Kwo J. Epitaxy from a Periodic Y-O Monolayer: Growth of Single-Crystal Hexagonal YAlO 3 Perovskite. Nanomaterials (Basel) 2020; 10:E1515. [PMID: 32748811 DOI: 10.3390/nano10081515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 07/26/2020] [Accepted: 07/28/2020] [Indexed: 11/24/2022]
Abstract
The role of an atomic-layer thick periodic Y–O array in inducing the epitaxial growth of single-crystal hexagonal YAlO3 perovskite (H-YAP) films was studied using high-angle annular dark-field and annular bright-field scanning transmission electron microscopy in conjunction with a spherical aberration-corrected probe and in situ reflection high-energy electron diffraction. We observed the Y–O array at the interface of amorphous atomic layer deposition (ALD) sub-nano-laminated (snl) Al2O3/Y2O3 multilayers and GaAs(111)A, with the first film deposition being three cycles of ALD-Y2O3. This thin array was a seed layer for growing the H-YAP from the ALD snl multilayers with 900 °C rapid thermal annealing (RTA). The annealed film only contained H-YAP with an excellent crystallinity and an atomically sharp interface with the substrate. The initial Y–O array became the bottom layer of H-YAP, bonding with Ga, the top layer of GaAs. Using a similar ALD snl multilayer, but with the first film deposition of three ALD-Al2O3 cycles, there was no observation of a periodic atomic array at the interface. RTA of the sample to 900 °C resulted in a non-uniform film, mixing amorphous regions and island-like H-YAP domains. The results indicate that the epitaxial H-YAP was induced from the atomic-layer thick periodic Y–O array, rather than from GaAs(111)A.
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Cheng CP, Chen WS, Cheng YT, Wan HW, Yang CY, Pi TW, Kwo J, Hong M. Atomic Nature of the Growth Mechanism of Atomic Layer Deposited High-κ Y 2O 3 on GaAs(001)-4 × 6 Based on in Situ Synchrotron Radiation Photoelectron Spectroscopy. ACS Omega 2018; 3:2111-2118. [PMID: 31458518 PMCID: PMC6641429 DOI: 10.1021/acsomega.7b01564] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 02/09/2018] [Indexed: 06/10/2023]
Abstract
Y2O3 was in situ deposited on a freshly grown molecular beam epitaxy GaAs(001)-4 × 6 surface by atomic layer deposition (ALD). In situ synchrotron radiation photoemission was used to study the mechanism of the tris(ethylcyclopentadienyl)yttrium [Y(CpEt)3] and H2O process. The exponential attenuation of Ga 3d photoelectrons confirmed the laminar growth of ALD-Y2O3. In the embryo stage of the first ALD half-cycle with only Y(CpEt)3, the precursors reside on the faulted As atoms and undergo a charge transfer to the bonded As atoms. The subsequent ALD half-cycle of H2O molecules removes the bonded As atoms, and the oxygen atoms bond with the underneath Ga atoms. The product of a line of Ga-O-Y bonds stabilizes the Y2O3 films on the GaAs substrate. The resulting coordinatively unsaturated Y-O pairs of Y2O3 open the next ALD series. The absence of Ga2O3, As2O3, and As2O5 states may play an important role in the attainment of low interfacial trap densities (D it) of <1012 cm-2 eV-1 in our established reports.
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Affiliation(s)
- Chiu-Ping Cheng
- Department
of Electrophysics, National Chiayi University, Chiayi 60004, Taiwan, ROC
| | - Wan-Sin Chen
- Graduate
Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan, ROC
| | - Yi-Ting Cheng
- Graduate
Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan, ROC
| | - Hsien-Wen Wan
- Graduate
Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan, ROC
| | - Cheng-Yeh Yang
- Department
of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC
| | - Tun-Wen Pi
- National
Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan, ROC
| | - Jueinai Kwo
- Department
of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC
| | - Minghwei Hong
- Graduate
Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan, ROC
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Bruhn T, Fimland BO, Vogt P. Electrophilic surface sites as precondition for the chemisorption of pyrrole on GaAs(001) surfaces. J Chem Phys 2015; 142:101903. [PMID: 25770492 DOI: 10.1063/1.4906117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
We report how the presence of electrophilic surface sites influences the adsorption mechanism of pyrrole on GaAs(001) surfaces. For this purpose, we have investigated the adsorption behavior of pyrrole on different GaAs(001) reconstructions with different stoichiometries and thus different surface chemistries. The interfaces were characterized by x-ray photoelectron spectroscopy, scanning tunneling microscopy, and by reflectance anisotropy spectroscopy in a spectral range between 1.5 and 5 eV. On the As-rich c(4 × 4) reconstruction that exhibits only nucleophilic surface sites, pyrrole was found to physisorb on the surface without any significant modification of the structural and electronic properties of the surface. On the Ga-rich GaAs(001)-(4 × 2)/(6 × 6) reconstructions which exhibit nucleophilic as well as electrophilic surface sites, pyrrole was found to form stable covalent bonds mainly to the electrophilic (charge deficient) Ga atoms of the surface. These results clearly demonstrate that the existence of electrophilic surface sites is a crucial precondition for the chemisorption of pyrrole on GaAs(001) surfaces.
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Affiliation(s)
- Thomas Bruhn
- Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr.36, D-10623 Berlin, Germany
| | - Bjørn-Ove Fimland
- Department of Electronics and Telecommunications, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Patrick Vogt
- Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr.36, D-10623 Berlin, Germany
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Burrows CW, Hatfield SA, Bastiman F, Bell GR. Interaction of Mn with GaAs and InSb: incorporation, surface reconstruction and nano-cluster formation. J Phys Condens Matter 2014; 26:395006. [PMID: 25191905 DOI: 10.1088/0953-8984/26/39/395006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The deposition of Mn on to reconstructed InSb and GaAs surfaces, without coincident As or Sb flux, has been studied by reflection high energy electron diffraction, atomic force microscopy and scanning tunnelling microscopy. On both Ga- and As-terminated GaAs(0 0 1), (2 × n) Mn-induced reconstruction domains arise with n = 2 for the most well ordered reconstructions. On the Ga-terminated (4 × 6), the Mn-induced (2 × 2) persists up to around 0.5 ML Mn followed by Mn nano-cluster formation. For deposition on initially β2(2 × 4)-reconstructed GaAs(0 0 1), the characteristic trench structure of the reconstruction is partially preserved even beyond 1 monolayer Mn coverage. On both the β2(2 × 4) and c(4 × 4) surfaces, MnAs-like nano-clusters form alongside the reconstruction changes. In contrast, there are no new Mn-induced surface reconstructions on InSb. Instead, the Sb-terminated surfaces of InSb (0 0 1), (1 1 1)A and (1 1 1)B revert to reconstructions characteristic of clean In-rich surfaces after well defined coverages of Mn proportional to the Sb content of the starting reconstruction. These surfaces are decorated with self-assembled MnSb nanoclusters. These results are discussed in terms of basic thermodynamic quantities and the generalized electron counting rule.
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Affiliation(s)
- C W Burrows
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
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Pi TW, Lin HY, Liu YT, Lin TD, Wertheim GK, Kwo J, Hong M. Atom-to-atom interactions for atomic layer deposition of trimethylaluminum on Ga-rich GaAs(001)-4 × 6 and As-rich GaAs(001)-2 × 4 surfaces: a synchrotron radiation photoemission study. Nanoscale Res Lett 2013; 8:169. [PMID: 23587341 PMCID: PMC3656810 DOI: 10.1186/1556-276x-8-169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 03/07/2013] [Indexed: 06/02/2023]
Abstract
High-resolution synchrotron radiation photoemission was employed to study the effects of atomic-layer-deposited trimethylaluminum (TMA) and water on Ga-rich GaAs(001)-4 × 6 and As-rich GaAs(001)-2 × 4 surfaces. No high charge states were found in either As 3d or Ga 3d core-level spectra before and after the deposition of the precursors. TMA adsorption does not disrupt the GaAs surface structure. For the (4 × 6) surface, the TMA precursor existed in both chemisorbed and physisorbed forms. In the former, TMA has lost a methyl group and is bonded to the As of the As-Ga dimer. Upon water purge, the dimethylaluminum-As group was etched off, allowing the now exposed Ga to bond with oxygen. Water also changed the physisorbed TMA into the As-O-Al(CH3)2 configuration. This configuration was also found in 1 cycle of TMA and water exposure of the (2 × 4) surface, but with a greater strength, accounting for the high interface defect density in the mid-gap region.
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Affiliation(s)
- Tun-Wen Pi
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Hsiao-Yu Lin
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Ya-Ting Liu
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Tsung-Da Lin
- Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | | | - Jueinai Kwo
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Minghwei Hong
- Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan
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Somaschini C, Bietti S, Sanguinetti S, Koguchi N, Fedorov A. Self-assembled GaAs/AlGaAs coupled quantum ring-disk structures by droplet epitaxy. Nanotechnology 2010; 21:125601. [PMID: 20182013 DOI: 10.1088/0957-4484/21/12/125601] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The fabrication, by droplet epitaxy, of a class of quantum nanostructures characterized by a regular, nanometres high, flat disks with a diameter of hundreds of nanometres and a hole at the centre encircled by a ring a few nanometres high, is presented here. A detailed analysis of the growth kinetics performed via in situ and ex situ probes allows us to propose a working model for the formation of these structures.
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Affiliation(s)
- C Somaschini
- L-NESS and Dipartimento di Scienza dei Materiali dell'Università degli Studi di Milano-Bicocca, Milano, Italy
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Abstract
We present the fabrication of GaAs/AlGaAs Multiple (from three to five) concentric nanoring structures by an innovative growth method based on droplet epitaxy and characterized by short time As supply to the Ga droplets at different substrate temperatures. The formation mechanism has been interpreted on the basis of a detailed ex situ and in situ characterization of nanostructure morphology and surface reconstruction. We introduce design criteria which will allow to obtain concentric quantum ring structures of the desired complexity.
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Affiliation(s)
- C Somaschini
- L-NESS and Dipartimento di Scienza dei Materiali, Universita di Milano Bicocca, Via Cozzi 53, I-20125, Milano, Italy
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