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Zhao YB, Lin SX, Fan QY, Zhang QD. Physical properties of Si 2Ge and SiGe 2 in hexagonal symmetry: First-principles calculations. CHINESE J CHEM PHYS 2022. [DOI: 10.1063/1674-0068/cjcp2008142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
We predict two novel group 14 element alloys Si2Ge and SiGe2 in P6222 phase in this work through first-principles calculations. The structures, stability, elastic anisotropy, electronic and thermodynamic properties of these two proposed alloys are investigated systematically. The proposed P6222-Si2Ge and P6222-SiGe2 have a hexagonal symmetry structure, and the phonon dispersion spectra and elastic constants indicate that these two alloys are dynamically and mechanically stable at ambient pressure. The elastic anisotropy properties of P6222-Si2Ge and P6222-SiGe2 are examined elaborately by illustrating the surface constructions of Young’s modulus, the contour surfaces of shear modulus, and the directional dependence of Poisson’s ratio; the differences with their corresponding group 14 element allotropes P6222-Si3 and P6222-Ge3 are also discussed and compared. Moreover, the Debye temperature and sound velocities are analyzed to study the thermodynamic properties of the proposed P6222-Si2Ge and P6222-SiGe2.
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Affiliation(s)
- Ying-bo Zhao
- School of Mechanical and Electrical Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China
| | - Shi-xuan Lin
- School of Mechanical and Electrical Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China
| | - Qing-yang Fan
- School of Information and Control Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China
| | - Qi-dong Zhang
- School of Microelectronics, Xidian University, Xi’an 710071, China
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2
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Milliken S, Thiessen AN, Cheong IT, O'Connor KM, Li Z, Hooper RW, Robidillo CJT, Veinot JGC. "Turning the dials": controlling synthesis, structure, composition, and surface chemistry to tailor silicon nanoparticle properties. NANOSCALE 2021; 13:16379-16404. [PMID: 34492675 DOI: 10.1039/d1nr04701a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Silicon nanoparticles (SiNPs) can be challenging to prepare with defined size, crystallinity, composition, and surface chemistry. As is the case for any nanomaterial, controlling these parameters is essential if SiNPs are to realize their full potential in areas such as alternative energy generation and storage, sensors, and medical imaging. Numerous teams have explored and established innovative synthesis methods, as well as surface functionalization protocols to control these factors. Furthermore, substantial effort has been expended to understand how the abovementioned parameters influence material properties. In the present review we provide a commentary highlighting the benefits and limitations of available methods for preparing silicon nanoparticles as well as demonstrations of tailoring optical and electronic properties through definition of structure (i.e., crystalline vs. amorphous), composition and surface chemistry. Finally, we highlight potential opportunities for future SiNP studies.
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Affiliation(s)
- Sarah Milliken
- Department of Chemistry, University of Alberta, Chemistry, Edmonton, Canada.
| | | | - I Teng Cheong
- Department of Chemistry, University of Alberta, Chemistry, Edmonton, Canada.
| | - Kevin M O'Connor
- Department of Chemistry, University of Alberta, Chemistry, Edmonton, Canada.
| | - Ziqi Li
- Department of Chemistry, University of Alberta, Chemistry, Edmonton, Canada.
| | - Riley W Hooper
- Department of Chemistry, University of Alberta, Chemistry, Edmonton, Canada.
| | | | - Jonathan G C Veinot
- Department of Chemistry, University of Alberta, Chemistry, Edmonton, Canada.
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3
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Wei Q, Tong W, Wei B, Zhang M, Peng X. Six new silicon phases with direct band gaps. Phys Chem Chem Phys 2019; 21:19963-19968. [PMID: 31478037 DOI: 10.1039/c9cp03128f] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Six new silicon phases with direct band gaps were found through silicon atomic substitution of carbon in the known carbon structures via high-throughput calculations. The six newly discovered Si phases are in the space groups of Im3[combining macron]m, C2/c, I4/mcm, I4/mmm, P21/m, and P4/mbm, respectively. Their crystal structures, stabilities, mechanical properties, elastic anisotropy, and electronic and optical properties were systematically studied using first-principles density functional theory calculations. All the new phases were proved to be thermodynamically and mechanically stable at ambient pressure. The direct band gap values in the range of 0.658-1.470 eV and the excellent optoelectronic properties of these six Si allotropes suggest that they are promising photovoltaic materials compared to diamond silicon.
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Affiliation(s)
- Qun Wei
- School of Physics and Optoelectronic Engineering, Xidian University, Xi'an 710071, P. R. China.
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4
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Joung I, Kim JY, Joo K, Lee J. Non-sequential protein structure alignment by conformational space annealing and local refinement. PLoS One 2019; 14:e0210177. [PMID: 30699145 PMCID: PMC6353097 DOI: 10.1371/journal.pone.0210177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 12/18/2018] [Indexed: 11/18/2022] Open
Abstract
Protein structure alignment is an important tool for studying evolutionary biology and protein modeling. A tool which intensively searches for the globally optimal non-sequential alignments is rarely found. We propose ALIGN-CSA which shows improvement in scores, such as DALI-score, SP-score, SO-score and TM-score over the benchmark set including 286 cases. We performed benchmarking of existing popular alignment scoring functions, where the dependence of the search algorithm was effectively eliminated by using ALIGN-CSA. For the benchmarking, we set the minimum block size to 4 to prevent much fragmented alignments where the biological relevance of small alignment blocks is hard to interpret. With this condition, globally optimal alignments were searched by ALIGN-CSA using the four scoring functions listed above, and TM-score is found to be the most effective in generating alignments with longer match lengths and smaller RMSD values. However, DALI-score is the most effective in generating alignments similar to the manually curated reference alignments, which implies that DALI-score is more biologically relevant score. Due to the high demand on computational resources of ALIGN-CSA, we also propose a relatively fast local refinement method, which can control the minimum block size and whether to allow the reverse alignment. ALIGN-CSA can be used to obtain much improved alignment at the cost of relatively more extensive computation. For faster alignment, we propose a refinement protocol that improves the score of a given alignment obtained by various external tools. All programs are available from http://lee.kias.re.kr.
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Affiliation(s)
- InSuk Joung
- Center for In Silico Protein Science, Korea Institute for Advanced Study, Seoul, Korea
| | - Jong Yun Kim
- Center for In Silico Protein Science, Korea Institute for Advanced Study, Seoul, Korea
| | - Keehyoung Joo
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul, Korea
- Center for Advanced Computation, Korea Institute for Advanced Study, Seoul, Korea
| | - Jooyoung Lee
- Center for In Silico Protein Science, Korea Institute for Advanced Study, Seoul, Korea
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul, Korea
- Center for Advanced Computation, Korea Institute for Advanced Study, Seoul, Korea
- * E-mail:
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6
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Chulapakorn T, Sychugov I, Saveda Suvanam S, Linnros J, Primetzhofer D, Hallén A. Influence of swift heavy ion irradiation on the photoluminescence of Si-nanoparticles and defects in SiO 2. NANOTECHNOLOGY 2017; 28:375603. [PMID: 28745617 DOI: 10.1088/1361-6528/aa824f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The influence of swift heavy ion (SHI) irradiation on the photoluminescence (PL) of silicon nanoparticles (SiNPs) and defects in SiO2-film is investigated. SiNPs were formed by implantation of 70 keV Si+ and subsequent thermal annealing to produce optically active SiNPs and to remove implantation-induced defects. Seven different ion species with energy between 3-36 MeV and fluence from 1011-1014 cm-2 were employed for irradiation of the implanted samples prior to the thermal annealing. Induced changes in defect and SiNP PL were characterized and correlated with the specific energy loss of the employed SHIs. We find that SHI irradiation, performed before the thermal annealing process, affects both defect and SiNP PL. The change of defect and SiNP PL due to SHI irradiation is found to show a threshold-like behaviour with respect to the electronic stopping power, where a decrease in defect PL and an anticorrelated increase in SiNP PL after the subsequent thermal annealing are observed for electronic stopping exceeding 3-5 keV nm-1. PL intensities are also compared as a function of total energy deposition and nuclear energy loss. The observed effects can be explained by ion track formation as well as a different type of annealing mechanisms active for SHI irradiation compared to the thermal annealing.
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Affiliation(s)
- Thawatchart Chulapakorn
- Uppsala University, Department of Physics and Astronomy, PO Box 516, SE-751 20 Uppsala, Sweden
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7
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Jantke LA, Karttunen AJ, Fässler TF. Slicing Diamond for More sp 3 Group 14 Allotropes Ranging from Direct Bandgaps to Poor Metals. Chemphyschem 2017; 18:1992-2006. [PMID: 28514503 DOI: 10.1002/cphc.201700290] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Revised: 05/09/2017] [Indexed: 11/06/2022]
Abstract
Considerable interest in novel Si allotropes has led to intense investigation of tetrahedral framework structures during the last years. Recently, a guide to deriving sp3 -Si allotropes from atom slabs of the diamond structure enabled a systematic deduction of several low-density modifications. Some of the Si networks were recognized as experimentally known frameworks, that is, so-called "chemi-inspired" structures. Herein we present nine novel Si networks obtained by modifying three-atom-thick slabs of a cubic diamond structure after smooth distortion by applying the same construction kit. Analysis of the structure-property relationships of these frameworks by using quantum-chemical methods shows that several of them possess direct bandgaps in the range suitable for light conversion. The construction kit was also applied to higher group 14 homologues Ge and Sn, and revealed interesting differences in the band structures and relative energies of the homologues. A new modification of Sn was identified as a poor metal, which denoted significant covalent-bond characteristics.
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Affiliation(s)
- Laura-Alice Jantke
- Department of Chemistry, Technische Universität München, Lichtenbergstr. 4, 85747, Garching, Germany
| | - Antti J Karttunen
- Department of Chemistry and Materials Science, Aalto University, 00076, Aalto, Finland
| | - Thomas F Fässler
- Department of Chemistry, Technische Universität München, Lichtenbergstr. 4, 85747, Garching, Germany
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Lee J, Lee IH, Joung I, Lee J, Brooks BR. Finding multiple reaction pathways via global optimization of action. Nat Commun 2017; 8:15443. [PMID: 28548089 PMCID: PMC5458546 DOI: 10.1038/ncomms15443] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 03/24/2017] [Indexed: 12/25/2022] Open
Abstract
Global searching for reaction pathways is a long-standing challenge in computational chemistry and biology. Most existing approaches perform only local searches due to computational complexity. Here we present a computational approach, Action-CSA, to find multiple diverse reaction pathways connecting fixed initial and final states through global optimization of the Onsager-Machlup action using the conformational space annealing (CSA) method. Action-CSA successfully overcomes large energy barriers via crossovers and mutations of pathways and finds all possible pathways of small systems without initial guesses on pathways. The rank order and the transition time distribution of multiple pathways are in good agreement with those of long Langevin dynamics simulations. The lowest action folding pathway of FSD-1 is consistent with recent experiments. The results show that Action-CSA is an efficient and robust computational approach to study the multiple pathways of complex reactions and large-scale conformational changes.
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Affiliation(s)
- Juyong Lee
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, Maryland 20892, USA
| | - In-Ho Lee
- Center for Materials Genome, Korea Research Institute of Standards and Science, Daejeon 34113, Republic of Korea
- Center for In Silico Protein Science, School of Computational Science, Korea Institute for Advanced Study, Seoul 02455, Republic of Korea
| | - InSuk Joung
- Center for In Silico Protein Science, School of Computational Science, Korea Institute for Advanced Study, Seoul 02455, Republic of Korea
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul 02455, Republic of Korea
| | - Jooyoung Lee
- Center for In Silico Protein Science, School of Computational Science, Korea Institute for Advanced Study, Seoul 02455, Republic of Korea
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul 02455, Republic of Korea
| | - Bernard R. Brooks
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, Maryland 20892, USA
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Bai C, Chai C, Fan Q, Liu Y, Yang Y. A Novel Silicon Allotrope in the Monoclinic Phase. MATERIALS (BASEL, SWITZERLAND) 2017; 10:E441. [PMID: 28772800 PMCID: PMC5506991 DOI: 10.3390/ma10040441] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 04/10/2017] [Accepted: 04/18/2017] [Indexed: 11/23/2022]
Abstract
This paper describes a new silicon allotrope in the P2/m space group found by first-principles calculations using the Cambridge Serial Total Energy Package (CASTEP) plane-wave code. The examined P2/m-Si belongs to the monoclinic crystal system. P2/m-Si is an indirect band-gap semiconductor with a band gap of 1.51 eV, as determined using the HSE06 hybrid functional. The elastic constants, phonon spectra and enthalpy indicate that P2/m-Si is mechanically, dynamically, and thermodynamically stable. P2/m-Si is a low-density (2.19 g/cm³) silicon allotrope. The value of B/G is less than 1.75, which indicates that the new allotrope is brittle. It is shown that the difference in the elastic anisotropy along different orientations is greater than that in other phases. Finally, to understand the thermodynamic properties of P2/m-Si, the thermal expansion coefficient α, the Debye temperature ΘD, and the heat capacities CP and CV are also investigated in detail.
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Affiliation(s)
- Chaogang Bai
- Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi'an 710071, China.
| | - Changchun Chai
- Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi'an 710071, China.
| | - Qingyang Fan
- Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi'an 710071, China.
| | - Yuqian Liu
- Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi'an 710071, China.
| | - Yintang Yang
- Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi'an 710071, China.
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10
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Dramatic Changes in Thermoelectric Power of Germanium under Pressure: Printing n-p Junctions by Applied Stress. Sci Rep 2017; 7:44220. [PMID: 28290495 PMCID: PMC5349603 DOI: 10.1038/srep44220] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 02/06/2017] [Indexed: 12/04/2022] Open
Abstract
Controlled tuning the electrical, optical, magnetic, mechanical and other characteristics of the leading semiconducting materials is one of the primary technological challenges. Here, we demonstrate that the electronic transport properties of conventional single-crystalline wafers of germanium may be dramatically tuned by application of moderate pressures. We investigated the thermoelectric power (Seebeck coefficient) of p– and n–type germanium under high pressure to 20 GPa. We established that an applied pressure of several GPa drastically shifts the electrical conduction to p–type. The p–type conduction is conserved across the semiconductor-metal phase transition at near 10 GPa. Upon pressure releasing, germanium transformed to a metastable st12 phase (Ge-III) with n–type semiconducting conductivity. We proposed that the unusual electronic properties of germanium in the original cubic-diamond-structured phase could result from a splitting of the “heavy” and “light” holes bands, and a related charge transfer between them. We suggested new innovative applications of germanium, e.g., in technologies of printing of n–p and n–p–n junctions by applied stress. Thus, our work has uncovered a new face of germanium as a ‘smart’ material.
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Bercx M, Sarmadian N, Saniz R, Partoens B, Lamoen D. First-principles analysis of the spectroscopic limited maximum efficiency of photovoltaic absorber layers for CuAu-like chalcogenides and silicon. Phys Chem Chem Phys 2016; 18:20542-9. [DOI: 10.1039/c6cp03468c] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
For low band gap compounds, it is possible to cross the SQ limit within the detailed balance framework.
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Affiliation(s)
- Marnik Bercx
- EMAT & CMT groups
- Department of Physics
- University of Antwerp
- Campus Groenenborger
- 2020 Antwerp
| | - Nasrin Sarmadian
- EMAT & CMT groups
- Department of Physics
- University of Antwerp
- Campus Groenenborger
- 2020 Antwerp
| | - Rolando Saniz
- EMAT & CMT groups
- Department of Physics
- University of Antwerp
- Campus Groenenborger
- 2020 Antwerp
| | - Bart Partoens
- EMAT & CMT groups
- Department of Physics
- University of Antwerp
- Campus Groenenborger
- 2020 Antwerp
| | - Dirk Lamoen
- EMAT & CMT groups
- Department of Physics
- University of Antwerp
- Campus Groenenborger
- 2020 Antwerp
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12
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Fan Q, Chai C, Wei Q, Yang Y. Two novel silicon phases with direct band gaps. Phys Chem Chem Phys 2016; 18:12905-13. [PMID: 27104737 DOI: 10.1039/c6cp00195e] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Based on density function theory with the ultrasoft pseudopotential scheme, we have systematically studied the structural stability, absorption spectra, electronic, optical and mechanical properties and minimum thermal conductivity of two novel silicon phases, Cm-32 silicon and P21/m silicon.
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Affiliation(s)
- Qingyang Fan
- Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices
- School of Microelectronics
- Xidian University
- Xi'an 710071
- P. R. China
| | - Changchun Chai
- Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices
- School of Microelectronics
- Xidian University
- Xi'an 710071
- P. R. China
| | - Qun Wei
- School of Physics and Optoelectronic Engineering
- Xidian University
- Xi'an 710071
- P. R. China
| | - Yintang Yang
- Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices
- School of Microelectronics
- Xidian University
- Xi'an 710071
- P. R. China
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