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Article Dans Une Revue Journal of Applied Physics Année : 2013

Amorphization and reduction of thermal conductivity in porous silicon by irradiation with swift heavy ions

Bruno Canut
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Séverine Gomès
Mykola Isaiev
Vladimir Lysenko

Résumé

In this article, we demonstrate that the thermal conductivity of nanostructured porous silicon is reduced by amorphization and also that this amorphous phase in porous silicon can be created by swift (high-energy) heavy ion irradiation. Porous silicon samples with 41%-75% porosity are irradiated with 110 MeV uranium ions at six different fluences. Structural characterisation by micro-Raman spectroscopy and SEM imaging show that swift heavy ion irradiation causes the creation of an amorphous phase in porous Si but without suppressing its porous structure. We demonstrate that the amorphization of porous silicon is caused by electronic-regime interactions, which is the first time such an effect is obtained in crystalline silicon with single-ion species. Furthermore, the impact on the thermal conductivity of porous silicon is studied by micro-Raman spectroscopy and scanning thermal microscopy. The creation of an amorphous phase in porous silicon leads to a reduction of its thermal conductivity, up to a factor of 3 compared to the non-irradiated sample. Therefore, this technique could be used to enhance the thermal insulation properties of porous Si. Finally, we show that this treatment can be combined with pre-oxidation at 300 °C, which is known to lower the thermal conductivity of porous Si, in order to obtain an even greater reduction.
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Dates et versions

hal-01663513 , version 1 (14-12-2017)

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Citer

Pascal J Newby, Bruno Canut, Jean‐marie Bluet, Séverine Gomès, Mykola Isaiev, et al.. Amorphization and reduction of thermal conductivity in porous silicon by irradiation with swift heavy ions. Journal of Applied Physics, 2013, 114 (1), pp.014903. ⟨10.1063/1.4812280⟩. ⟨hal-01663513⟩
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