skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Non-monotonic temperature dependence of radiation defect dynamics in silicon carbide

Abstract

Understanding response of solids to particle irradiation remains a major materials physics challenge. This applies even to SiC, which is a prototypical nuclear ceramic and wide-band-gap semiconductor material. The lack of predictability is largely related to the complex, dynamic nature of radiation defect formation. Here, we use a novel pulsed-ion-beam method to study dynamic annealing in 4H-SiC ion-bombarded in the temperature range of 25–250 °C. We find that, while the defect recombination efficiency shows an expected monotonic increase with increasing temperature, the defect lifetime exhibits a non-monotonic temperature dependence with a maximum at ~100 °C. This finding indicates a change in the dominant defect interaction mechanism at ~100 °C. As a result, the understanding of radiation defect dynamics may suggest new paths to designing radiation-resistant materials.

Authors:
 [1];  [2];  [3];  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Texas A&M Univ., College Station, TX (United States)
  3. Texas A&M Univ., College Station, TX (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1297652
Report Number(s):
LLNL-JRNL-677429
Journal ID: ISSN 2045-2322; TRN: US1601834
Grant/Contract Number:
AC52-07NA27344
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 6; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY

Citation Formats

Bayu Aji, L. B., Wallace, J. B., Shao, L., and Kucheyev, S. O. Non-monotonic temperature dependence of radiation defect dynamics in silicon carbide. United States: N. p., 2016. Web. doi:10.1038/srep30931.
Bayu Aji, L. B., Wallace, J. B., Shao, L., & Kucheyev, S. O. Non-monotonic temperature dependence of radiation defect dynamics in silicon carbide. United States. doi:10.1038/srep30931.
Bayu Aji, L. B., Wallace, J. B., Shao, L., and Kucheyev, S. O. Wed . "Non-monotonic temperature dependence of radiation defect dynamics in silicon carbide". United States. doi:10.1038/srep30931. https://www.osti.gov/servlets/purl/1297652.
@article{osti_1297652,
title = {Non-monotonic temperature dependence of radiation defect dynamics in silicon carbide},
author = {Bayu Aji, L. B. and Wallace, J. B. and Shao, L. and Kucheyev, S. O.},
abstractNote = {Understanding response of solids to particle irradiation remains a major materials physics challenge. This applies even to SiC, which is a prototypical nuclear ceramic and wide-band-gap semiconductor material. The lack of predictability is largely related to the complex, dynamic nature of radiation defect formation. Here, we use a novel pulsed-ion-beam method to study dynamic annealing in 4H-SiC ion-bombarded in the temperature range of 25–250 °C. We find that, while the defect recombination efficiency shows an expected monotonic increase with increasing temperature, the defect lifetime exhibits a non-monotonic temperature dependence with a maximum at ~100 °C. This finding indicates a change in the dominant defect interaction mechanism at ~100 °C. As a result, the understanding of radiation defect dynamics may suggest new paths to designing radiation-resistant materials.},
doi = {10.1038/srep30931},
journal = {Scientific Reports},
number = ,
volume = 6,
place = {United States},
year = {Wed Aug 03 00:00:00 EDT 2016},
month = {Wed Aug 03 00:00:00 EDT 2016}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 7works
Citation information provided by
Web of Science

Save / Share:
  • The measured thermodynamic phase diagram of the quasi-two-dimensional magnet [Cu(HF{sub 2})(pyz){sub 2}]BF{sub 4}(pyz=pyrazine=N{sub 2}C{sub 4}H{sub 4}) exhibits an unusual nonmonotonic dependence of the Neel temperature T{sub N} as a function of magnetic field H. The nonmonotonic behavior of T{sub N}(H) results from two competing effects induced by the field: while H suppresses the amplitude of the order parameter by polarizing the spins along a given direction, it also reduces the phase fluctuations by changing the order parameter space from the sphere S{sup 2} to the circle S{sup 1}. The latter effect dominates at low fields only if the system ismore » close enough to its lower critical dimension (d{sub c} = 2), i.e., when fluctuations become important. Our theoretical results reproduce the measured phase diagram and demonstrate that this unusual effect is realized in [Cu(HF{sub 2})(pyz){sub 2}]BF{sub 4}.« less
  • We examine the temperature dependence of thermopower in the single-band Hubbard model using dynamical mean-field theory. The strong Coulomb interaction brings about the coherent-to-incoherent crossover as temperature increases. As a result, the thermopower exhibits nonmonotonic temperature dependence and asymptotically approaches values given by the Mott-Heikes formula. In the light of our theoretical result, we discuss the thermopower in some transition metal oxides. The magnetic field dependence of the thermopower is also discussed.
  • In this work, we investigate the processes leading to the room-temperature growth of silicon carbide thin films by supersonic molecular beam epitaxy technique. We present experimental data showing that the collision of fullerene on a silicon surface induces strong chemical-physical perturbations and, for sufficient velocity, disruption of molecular bonds, and cage breaking with formation of nanostructures with different stoichiometric character. We show that in these out-of-equilibrium conditions, it is necessary to go beyond the standard implementations of density functional theory, as ab initio methods based on the Born-Oppenheimer approximation fail to capture the excited-state dynamics. In particular, we analyse themore » Si-C{sub 60} collision within the non-adiabatic nuclear dynamics framework, where stochastic hops occur between adiabatic surfaces calculated with time-dependent density functional theory. This theoretical description of the C{sub 60} impact on the Si surface is in good agreement with our experimental findings.« less
  • Density of defect states of aluminum nitride (AlN) films deposited by rf magnetron sputtering on <100>-oriented silicon (Si) and 4H-silicon carbide (4H-SiC) have been investigated using the deep-level-transient-spectroscopy technique. The films were grown at room temperature with varying nitrogen flow from 4 to 20 sccm and a constant argon flow of 10 sccm. In general the defect densities of AlN are lower when grown on 4H-SiC substrates than on Si substrates. The observed defect levels are identified as donor-like triplet of nitrogen vacancy and DX-like centers. Defects located at 0.35-0.42 eV below the conduction band, attributed to dangling bonds ofmore » nitrogen atoms, are seen in samples grown with higher nitrogen flow rate. Shallow level defects, observed at approximately 0.1 eV below the conduction band, can be attributed to the recently discovered prismatic staking fault in the AlN atomic structure.« less