Amorphization of Ge nanocrystals embedded in amorphous silica under ion irradiation

Flyura Djurabekova, Marie Backman, Olli H Pakarinen, Kai Nordlund, Leandro L Araujo, Mark C Ridgway

    Forskningsoutput: TidskriftsbidragKonferensartikelVetenskapligPeer review

    Sammanfattning

    One of the key reasons why nanoscale materials behave differently from their bulk counterparts is that a large fraction of atoms reside at surfaces or interfaces. For instance, the melting point, hardness and even crystal structure of a nanocrystal can be dramatically different from that of the same element or compound in its conventional phase. Of particular interest from an ion-beam modification point of view is how much the structural transformations induced by energetic ions in nanocrystals differ from those in the bulk phase. Using a combination of molecular dynamics (MD) computer simulations and Extended X-ray Absorption Fine Structure (EXAFS) experiments, we show that the crystalline-to-amorphous transition in Ge nanocrystals occurs at a dose which is significantly (more than an order of magnitude) lower than that in the bulk phase. The MD simulations indicate that this is related to the outermost part of a structured nanocrystal being subjected to an additional stress delivered by the amorphous surroundings. These results show that conventional models based on irradiation of bulk materials can not be used to estimate the susceptibility of nanocrystals to phase transitions. (C) 2009 Elsevier B.V. All rights reserved.
    Originalspråkengelska
    TidskriftNuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms
    Volym267
    Sidor (från-till)1235-1238
    Antal sidor4
    ISSN0168-583X
    DOI
    StatusPublicerad - 2009
    MoE-publikationstypA4 Artikel i en konferenspublikation
    EvenemangUnknown host publication - , Holland
    Varaktighet: 1 jan 1800 → …

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    title = "Amorphization of Ge nanocrystals embedded in amorphous silica under ion irradiation",
    abstract = "One of the key reasons why nanoscale materials behave differently from their bulk counterparts is that a large fraction of atoms reside at surfaces or interfaces. For instance, the melting point, hardness and even crystal structure of a nanocrystal can be dramatically different from that of the same element or compound in its conventional phase. Of particular interest from an ion-beam modification point of view is how much the structural transformations induced by energetic ions in nanocrystals differ from those in the bulk phase. Using a combination of molecular dynamics (MD) computer simulations and Extended X-ray Absorption Fine Structure (EXAFS) experiments, we show that the crystalline-to-amorphous transition in Ge nanocrystals occurs at a dose which is significantly (more than an order of magnitude) lower than that in the bulk phase. The MD simulations indicate that this is related to the outermost part of a structured nanocrystal being subjected to an additional stress delivered by the amorphous surroundings. These results show that conventional models based on irradiation of bulk materials can not be used to estimate the susceptibility of nanocrystals to phase transitions. (C) 2009 Elsevier B.V. All rights reserved.",
    keywords = "114 Physical sciences",
    author = "Flyura Djurabekova and Marie Backman and Pakarinen, {Olli H} and Kai Nordlund and Araujo, {Leandro L} and Ridgway, {Mark C}",
    note = "Volume: 267 Host publication title: 16th International Conference on Ion Beam Modification of Materials Proceeding volume:",
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    Amorphization of Ge nanocrystals embedded in amorphous silica under ion irradiation. / Djurabekova, Flyura; Backman, Marie; Pakarinen, Olli H; Nordlund, Kai; Araujo, Leandro L; Ridgway, Mark C.

    I: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms, Vol. 267, 2009, s. 1235-1238.

    Forskningsoutput: TidskriftsbidragKonferensartikelVetenskapligPeer review

    TY - JOUR

    T1 - Amorphization of Ge nanocrystals embedded in amorphous silica under ion irradiation

    AU - Djurabekova, Flyura

    AU - Backman, Marie

    AU - Pakarinen, Olli H

    AU - Nordlund, Kai

    AU - Araujo, Leandro L

    AU - Ridgway, Mark C

    N1 - Volume: 267 Host publication title: 16th International Conference on Ion Beam Modification of Materials Proceeding volume:

    PY - 2009

    Y1 - 2009

    N2 - One of the key reasons why nanoscale materials behave differently from their bulk counterparts is that a large fraction of atoms reside at surfaces or interfaces. For instance, the melting point, hardness and even crystal structure of a nanocrystal can be dramatically different from that of the same element or compound in its conventional phase. Of particular interest from an ion-beam modification point of view is how much the structural transformations induced by energetic ions in nanocrystals differ from those in the bulk phase. Using a combination of molecular dynamics (MD) computer simulations and Extended X-ray Absorption Fine Structure (EXAFS) experiments, we show that the crystalline-to-amorphous transition in Ge nanocrystals occurs at a dose which is significantly (more than an order of magnitude) lower than that in the bulk phase. The MD simulations indicate that this is related to the outermost part of a structured nanocrystal being subjected to an additional stress delivered by the amorphous surroundings. These results show that conventional models based on irradiation of bulk materials can not be used to estimate the susceptibility of nanocrystals to phase transitions. (C) 2009 Elsevier B.V. All rights reserved.

    AB - One of the key reasons why nanoscale materials behave differently from their bulk counterparts is that a large fraction of atoms reside at surfaces or interfaces. For instance, the melting point, hardness and even crystal structure of a nanocrystal can be dramatically different from that of the same element or compound in its conventional phase. Of particular interest from an ion-beam modification point of view is how much the structural transformations induced by energetic ions in nanocrystals differ from those in the bulk phase. Using a combination of molecular dynamics (MD) computer simulations and Extended X-ray Absorption Fine Structure (EXAFS) experiments, we show that the crystalline-to-amorphous transition in Ge nanocrystals occurs at a dose which is significantly (more than an order of magnitude) lower than that in the bulk phase. The MD simulations indicate that this is related to the outermost part of a structured nanocrystal being subjected to an additional stress delivered by the amorphous surroundings. These results show that conventional models based on irradiation of bulk materials can not be used to estimate the susceptibility of nanocrystals to phase transitions. (C) 2009 Elsevier B.V. All rights reserved.

    KW - 114 Physical sciences

    U2 - 10.1016/j.nimb.2009.01.022

    DO - 10.1016/j.nimb.2009.01.022

    M3 - Conference article

    VL - 267

    SP - 1235

    EP - 1238

    JO - Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms

    JF - Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms

    SN - 0168-583X

    ER -