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Title: Dynamic nuclear polarization of {sup 29}Si nuclei in isotopically controlled phosphorus doped silicon

Abstract

Dynamic nuclear polarization (DNP) of {sup 29}Si nuclei in isotopically controlled silicon single crystals with the {sup 29}Si isotope abundance f{sub 29Si} varied from 1.2% to 99.2% is reported. It was found that both the DNP enhancement and {sup 29}Si nuclear spin-lattice relaxation time under saturation of the electron paramagnetic resonance transitions of phosphorus donors increase with the decrease in the {sup 29}Si abundance. A remarkably large steady-state DNP enhancement, E{sup ss}=2680 which is comparable to the theoretical upper limit of 3310, has been achieved through the ''resolved'' solid effect that has been identified clearly in the f{sub 29Si}=1.2% sample. The DNP enhancement depends not only on the {sup 29}Si abundance but also on the electron spin-lattice relaxation time that can be controlled by temperature and/or illumination. The linewidth of {sup 29}Si NMR spectra after DNP shows a linear dependence on f{sub 29Si} for f{sub 29Si}{<=}10% and changes to a square-root dependence for f{sub 29Si}{>=}50%. Comparison of experimentally determined nuclear polarization time with nuclear spin diffusion coefficients indicates that the rate of DNP is limited by the polarization transfer rather than by spin diffusion.

Authors:
; ; ; ;  [1];  [2]
  1. School of Fundamental Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)
  2. (Russian Federation)
Publication Date:
OSTI Identifier:
21287045
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter and Materials Physics; Journal Volume: 80; Journal Issue: 4; Other Information: DOI: 10.1103/PhysRevB.80.045201; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COMPARATIVE EVALUATIONS; DIFFUSION; DINITROPHENOL; DOPED MATERIALS; ELECTRON SPIN RESONANCE; ELECTRONS; ILLUMINANCE; MONOCRYSTALS; NMR SPECTRA; NUCLEAR MAGNETIC RESONANCE; PARAMAGNETISM; PHOSPHORUS ADDITIONS; POLARIZATION; SATURATION; SILICON; SILICON 29; SOLIDS; SPIN; SPIN-LATTICE RELAXATION; STEADY-STATE CONDITIONS

Citation Formats

Hayashi, Hiroshi, Itahashi, Tatsumasa, Itoh, Kohei M., Vlasenko, Leonid S., Vlasenko, Marina P., and A. F. Ioffe Physico-Technical Institute, 194021 Saint Petersburg. Dynamic nuclear polarization of {sup 29}Si nuclei in isotopically controlled phosphorus doped silicon. United States: N. p., 2009. Web. doi:10.1103/PHYSREVB.80.045201.
Hayashi, Hiroshi, Itahashi, Tatsumasa, Itoh, Kohei M., Vlasenko, Leonid S., Vlasenko, Marina P., & A. F. Ioffe Physico-Technical Institute, 194021 Saint Petersburg. Dynamic nuclear polarization of {sup 29}Si nuclei in isotopically controlled phosphorus doped silicon. United States. doi:10.1103/PHYSREVB.80.045201.
Hayashi, Hiroshi, Itahashi, Tatsumasa, Itoh, Kohei M., Vlasenko, Leonid S., Vlasenko, Marina P., and A. F. Ioffe Physico-Technical Institute, 194021 Saint Petersburg. Wed . "Dynamic nuclear polarization of {sup 29}Si nuclei in isotopically controlled phosphorus doped silicon". United States. doi:10.1103/PHYSREVB.80.045201.
@article{osti_21287045,
title = {Dynamic nuclear polarization of {sup 29}Si nuclei in isotopically controlled phosphorus doped silicon},
author = {Hayashi, Hiroshi and Itahashi, Tatsumasa and Itoh, Kohei M. and Vlasenko, Leonid S. and Vlasenko, Marina P. and A. F. Ioffe Physico-Technical Institute, 194021 Saint Petersburg},
abstractNote = {Dynamic nuclear polarization (DNP) of {sup 29}Si nuclei in isotopically controlled silicon single crystals with the {sup 29}Si isotope abundance f{sub 29Si} varied from 1.2% to 99.2% is reported. It was found that both the DNP enhancement and {sup 29}Si nuclear spin-lattice relaxation time under saturation of the electron paramagnetic resonance transitions of phosphorus donors increase with the decrease in the {sup 29}Si abundance. A remarkably large steady-state DNP enhancement, E{sup ss}=2680 which is comparable to the theoretical upper limit of 3310, has been achieved through the ''resolved'' solid effect that has been identified clearly in the f{sub 29Si}=1.2% sample. The DNP enhancement depends not only on the {sup 29}Si abundance but also on the electron spin-lattice relaxation time that can be controlled by temperature and/or illumination. The linewidth of {sup 29}Si NMR spectra after DNP shows a linear dependence on f{sub 29Si} for f{sub 29Si}{<=}10% and changes to a square-root dependence for f{sub 29Si}{>=}50%. Comparison of experimentally determined nuclear polarization time with nuclear spin diffusion coefficients indicates that the rate of DNP is limited by the polarization transfer rather than by spin diffusion.},
doi = {10.1103/PHYSREVB.80.045201},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 4,
volume = 80,
place = {United States},
year = {Wed Jul 15 00:00:00 EDT 2009},
month = {Wed Jul 15 00:00:00 EDT 2009}
}
  • A nuclear magnetic resonance (NMR) study was performed with n-type silicon single crystals containing {sup 29}Si isotope abundance f ranges from 1.2% to 99.2%. The nuclear spin diffusion coefficient D has been determined from the linewidth of significantly enhanced {sup 29}Si NMR signals utilizing a developed dynamic nuclear polarization (DNP) method. The {sup 29}Si NMR linewidth depends linearly on f, at least when f<10%, and approaches {proportional_to}f{sup 1/2} dependence when f>50%. The estimated {sup 29}Si nuclear spin diffusion time T{sub sd} between phosphorus atoms used for DNP is more than ten times shorter than the nuclear polarization time T{sub 1}{supmore » p} of {sup 29}Si nuclei around phosphorus. Therefore, the regime of 'rapid spin diffusion' is realized in the DNP experiments.« less
  • The extension of the Overhauser effect to semi-conductors has resulted in considerable augmentation of the nuclear resonance signal caused by Si/sup 29/ in saturating the resonance of the conducting electrons of a sample of silicon. The nuclear polarization thus obtained lasts for several minutes at ordinary temperature. (tr-auth)
  • The elastic scattering of /sup 16/O ions by the nuclei/sup 28//sup ,//sup 29//sup ,//sup 30/ Si at the two collision energies E = 54.7 and 60 MeV is analyzed. On the basis of a microscopic calculation of the imaginary part of the optical potential the relation between the absorption and the shell structure of the colliding nuclei is analyzed. The dependence of the anomalous scattering at large angles on the choice of the target nucleus is studied by decomposing the amplitude into near and distant components.
  • We present experimental results of impurity and self-diffusion in an isotopically controlled silicon heterostructure extrinsically doped with phosphorus. As a consequence of extrinsic doping, the concentration of singly negatively charged native defects is enhanced and the role of these native defect charge states in the simultaneous phosphorus and Si self-diffusion can be determined. Multilayers of isotopically controlled {sup 28}Si and natural silicon enable simultaneous analysis of {sup 30}Si self-diffusion into the {sup 28}Si enriched layers and phosphorus diffusion throughout the multilayer structure. An amorphous 260 nm thick Si cap layer was deposited on top of the Si isotope heterostructure. Themore » phosphorus ions were implanted to a depth such that all the radiation damage resided inside this amorphous cap layer, preventing the generation of excess native defects and enabling the determination of the Si self-diffusion coefficient and the phosphorus diffusivity under equilibrium conditions. These samples were annealed at temperatures between 950 and 1100 C to study the diffusion. Detailed analysis of the diffusion process was performed on the basis of a P diffusion model which involves neutral and positively charged mobile P species and neutral and singly negatively charged self-interstitial.« less
  • The {sup 29}Si CP/MAS spectra of the reaction products of hexamethyldisilazane (HMDS) with porous aluminophosphates showed distinct resonances from trimethylsiloxane groups attached to both aluminum and phosphorus. The relative intensity of the two signals varied according to the composition of the carrier; however, integration always indicated a higher phosphorous to aluminum ratio in the silane product than expected from the bulk composition. This can be explained by either a nonhomogeneous distribution of phosphorus and aluminum centers or a hindered reaction mechanism at the surface. In either case, the reaction products of HMDS with the aluminophosphate surface can be used tomore » predict the behavior of other substrates at this surface, such as catalytically active chromium compounds. The spectra of the reaction products obtained with dichlorodimethylsilane suggest not only dimethylsiloxane groups bridging aluminum/phosphorus centers but also phosphorus/phosphorus and aluminum/aluminum bridges.« less