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Smith JS, Budi A, Per MC, Vogt N, Drumm DW, Hollenberg LCL, Cole JH, Russo SP. Ab initio calculation of energy levels for phosphorus donors in silicon. Sci Rep 2017; 7:6010. [PMID: 28729674 PMCID: PMC5519722 DOI: 10.1038/s41598-017-06296-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 06/09/2017] [Indexed: 11/09/2022] Open
Abstract
The s manifold energy levels for phosphorus donors in silicon are important input parameters for the design and modeling of electronic devices on the nanoscale. In this paper we calculate these energy levels from first principles using density functional theory. The wavefunction of the donor electron's ground state is found to have a form that is similar to an atomic s orbital, with an effective Bohr radius of 1.8 nm. The corresponding binding energy of this state is found to be 41 meV, which is in good agreement with the currently accepted value of 45.59 meV. We also calculate the energies of the excited 1s(T 2) and 1s(E) states, finding them to be 32 and 31 meV respectively.
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Affiliation(s)
- J S Smith
- Chemical and Quantum Physics, School of Science, RMIT University, Melbourne, VIC, 3001, Australia.
| | - A Budi
- Materials Chemistry, Nano-Science Center, Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, København Ø, Denmark
| | - M C Per
- Data 61 CSIRO, Door 34 Goods Shed, Village Street, Docklands, VIC, 3008, Australia
| | - N Vogt
- Chemical and Quantum Physics, School of Science, RMIT University, Melbourne, VIC, 3001, Australia
| | - D W Drumm
- Chemical and Quantum Physics, School of Science, RMIT University, Melbourne, VIC, 3001, Australia.,Australian Research Council Centre of Excellence for Nanoscale BioPhotonics, School of Science, RMIT University, Melbourne, VIC, 3001, Australia
| | - L C L Hollenberg
- Centre for Quantum Computation and Communication Technology, School of Physics, The University of Melbourne, Parkville, 3010, Victoria, Australia
| | - J H Cole
- Chemical and Quantum Physics Group, ARC Centre of Excellence in Exciton Science, School of Science, RMIT University, Melbourne, 3000, Australia
| | - S P Russo
- Chemical and Quantum Physics Group, ARC Centre of Excellence in Exciton Science, School of Science, RMIT University, Melbourne, 3000, Australia
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Abstract
Magnonics is an emerging field with potential applications in classical and quantum information processing. Freely propagating magnons in two-dimensional media are subject to dispersion, which limits their effective range and utility as information carriers. We show the design of a confining magnonic waveguide created by two surface current carrying wires placed above a spin-sheet, which can be used as a primitive for reconfigurable magnonic circuitry. We theoretically demonstrate the ability of such guides to counter the transverse dispersion of the magnon in a spin-sheet, thus extending the range of the magnon. A design of a magnonic directional coupler and controllable Michelson interferometer is shown, demonstrating its utility for information processing tasks.
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Weber B, Ryu H, Tan YHM, Klimeck G, Simmons MY. Limits to metallic conduction in atomic-scale quasi-one-dimensional silicon wires. PHYSICAL REVIEW LETTERS 2014; 113:246802. [PMID: 25541793 DOI: 10.1103/physrevlett.113.246802] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Indexed: 06/04/2023]
Abstract
The recent observation of ultralow resistivity in highly doped, atomic-scale silicon wires has sparked interest in what limits conduction in these quasi-1D systems. Here we present electron transport measurements of gated Si:P wires of widths 4.6 and 1.5 nm. At 4.6 nm we find an electron mobility, μ(el)≃60 cm²/V s, in excellent agreement with that of macroscopic Hall bars. Metallic conduction persists to millikelvin temperatures where we observe Gaussian conductance fluctuations of order δG∼e²/h. In thinner wires (1.5 nm), metallic conduction breaks down at G≲e²/h, where localization of carriers leads to Coulomb blockade. Metallic behavior is explained by the large carrier densities in Si:P δ-doped systems, allowing the occupation of all six valleys of the silicon conduction band, enhancing the number of 1D channels and hence the localization length.
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Affiliation(s)
- Bent Weber
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Hoon Ryu
- National Institute of Supercomputing and Networking, KISTI, Daejeon 305-806, South Korea
| | - Y-H Matthias Tan
- Network for Computational Nanotechnology, Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA
| | - Gerhard Klimeck
- Network for Computational Nanotechnology, Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA
| | - Michelle Y Simmons
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
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Shen Z, Hu Z, Wang W, Lee SF, Chan DKL, Li Y, Gu T, Yu JC. Crystalline phosphorus fibers: controllable synthesis and visible-light-driven photocatalytic activity. NANOSCALE 2014; 6:14163-14167. [PMID: 25325830 DOI: 10.1039/c4nr04250f] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
An efficient method is developed for the synthesis of single crystalline fibrous phosphorus submicron materials. Via the chemical vapor deposition (CVD) technique, fibrous phosphorus fibers with diameters from ∼150 nm to 2 μm were prepared directly from amorphous red phosphorus. The as-prepared fibrous phosphorus exhibited interesting photocatalytic properties.
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Affiliation(s)
- Zhurui Shen
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
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Mazzola F, Edmonds MT, Høydalsvik K, Carter DJ, Marks NA, Cowie BCC, Thomsen L, Miwa J, Simmons MY, Wells JW. Determining the electronic confinement of a subsurface metallic state. ACS NANO 2014; 8:10223-10228. [PMID: 25243326 DOI: 10.1021/nn5045239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Dopant profiles in semiconductors are important for understanding nanoscale electronics. Highly conductive and extremely confined phosphorus doping profiles in silicon, known as Si:P δ-layers, are of particular interest for quantum computer applications, yet a quantitative measure of their electronic profile has been lacking. Using resonantly enhanced photoemission spectroscopy, we reveal the real-space breadth of the Si:P δ-layer occupied states and gain a rare view into the nature of the confined orbitals. We find that the occupied valley-split states of the δ-layer, the so-called 1Γ and 2Γ, are exceptionally confined with an electronic profile of a mere 0.40 to 0.52 nm at full width at half-maximum, a result that is in excellent agreement with density functional theory calculations. Furthermore, the bulk-like Si 3pz orbital from which the occupied states are derived is sufficiently confined to lose most of its pz-like character, explaining the strikingly large valley splitting observed for the 1Γ and 2Γ states.
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Affiliation(s)
- Federico Mazzola
- Department of Physics, Norwegian University of Science and Technology (NTNU) , N-7491 Trondheim, Norway
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Drumm DW, Per MC, Budi A, Hollenberg LCL, Russo SP. Ab initio electronic properties of dual phosphorus monolayers in silicon. NANOSCALE RESEARCH LETTERS 2014; 9:443. [PMID: 25246862 PMCID: PMC4158386 DOI: 10.1186/1556-276x-9-443] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 08/15/2014] [Indexed: 05/29/2023]
Abstract
IN THE MIDST OF THE EPITAXIAL CIRCUITRY REVOLUTION IN SILICON TECHNOLOGY, WE LOOK AHEAD TO THE NEXT PARADIGM SHIFT: effective use of the third dimension - in particular, its combination with epitaxial technology. We perform ab initio calculations of atomically thin epitaxial bilayers in silicon, investigating the fundamental electronic properties of monolayer pairs. Quantitative band splittings and the electronic density are presented, along with effects of the layers' relative alignment and comments on disordered systems, and for the first time, the effective electronic widths of such device components are calculated.
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Affiliation(s)
- Daniel W Drumm
- Theoretical Chemical and Quantum Physics, School of Applied Sciences, RMIT University, Melbourne, VIC 3001, Australia
- School of Physics, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Manolo C Per
- Theoretical Chemical and Quantum Physics, School of Applied Sciences, RMIT University, Melbourne, VIC 3001, Australia
- CSIRO Virtual Nanoscience Laboratory, 343 Royal Parade, Parkville, VIC 3052, Australia
| | - Akin Budi
- School of Physics, The University of Melbourne, Parkville, VIC 3010, Australia
- Now at NanoGeoScience, Nano-Science Centre, University of Copenhagen, Universitetsparken 5, København Ø 2100, Denmark
| | - Lloyd CL Hollenberg
- School of Physics, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Salvy P Russo
- Theoretical Chemical and Quantum Physics, School of Applied Sciences, RMIT University, Melbourne, VIC 3001, Australia
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Klymenko MV, Remacle F. Electronic states and wavefunctions of diatomic donor molecular ions in silicon: multi-valley envelope function theory. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:065302. [PMID: 24451236 DOI: 10.1088/0953-8984/26/6/065302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Using the Burt-Foreman envelope function theory and effective mass approximation, we develop a theoretical model for an arbitrary number of interacting donor atoms embedded in silicon which reproduces the electronic energy spectrum with high computational efficiency, taking into account the effective mass anisotropy and the valley-orbit coupling. We show that the variation of the relative magnitudes of the electronic coupling between the donor atoms with respect to the valley-orbit coupling as a function of the internuclear distance leads to different kinds of spatial interference patterns of the wavefunction. We also report on the impact of the orientation of the diatomic phosphorus donor molecular ion in the crystal lattice on the ionization energy and on the energy separation between the ground state and the lowest excited state.
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Ryu H, Lee S, Weber B, Mahapatra S, Hollenberg LCL, Simmons MY, Klimeck G. Atomistic modeling of metallic nanowires in silicon. NANOSCALE 2013; 5:8666-8674. [PMID: 23897026 DOI: 10.1039/c3nr01796f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Scanning tunneling microscope (STM) lithography has recently demonstrated the ultimate in device scaling with buried, conducting nanowires just a few atoms wide and the realization of single atom transistors, where a single P atom has been placed inside a transistor architecture with atomic precision accuracy. Despite the dimensions of the critical parts of these devices being defined by a small number of P atoms, the device electronic properties are influenced by the surrounding 10(4) to 10(6) Si atoms. Such effects are hard to capture with most modeling approaches, and prior to this work no theory existed that could explore the realistic size of the complete device in which both dopant disorder and placement are important. This work presents a comprehensive study of the electronic and transport properties of ultra-thin (<10 nm wide) monolayer highly P δ-doped Si (Si:P) nanowires in a fully atomistic self-consistent tight-binding approach. This atomistic approach covering large device volumes allows for a systematic study of disorder on the physical properties of the nanowires. Excellent quantitative agreement is observed with recent resistance measurements of STM-patterned nanowires [Weber et al., Science, 2012, 335, 64], confirming the presence of metallic behavior at the scaling limit. At high doping densities the channel resistance is shown to be insensitive to the exact channel dopant placement highlighting their future use as metallic interconnects. This work presents the first theoretical study of Si:P nanowires that are realistically extended and disordered, providing a strong theoretical foundation for the design and understanding of atomic-scale electronics.
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Affiliation(s)
- Hoon Ryu
- National Institute of Supercomputing and Networking, Korea Institute of Science and Technology Information, Daejeon 305-806, Republic of Korea
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