Electron transport through composite SiO2(Si)&FexOy(Fe) thin films containing Si and Fe nanoclusters

• Published in: Journal of alloys and compounds Vol. 903; p. 163892
• Main Authors: Kizjak, A.Yu, Evtukh, A.A., Bratus, O.L., Antonin, S.V., Ievtukh, V.A., Pylypova, O.V., Fedotov, A.K.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15.05.2022; Elsevier BV
• Subjects: Conduction bands; Direct current; Electric fields; Electron transport; Electron transport mechanisms; Electron traps; Hopping conduction; Nanoclusters; Nanocomposite film; Oxide matrices; Si and Fe nanoclusters; Silicon dioxide; Temperature; Temperature dependence; Thin films; Electron traps; Electron transport mechanisms; Oxide matrices; Si and Fe nanoclusters; Nanocomposite film
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2022.163892

•Granular structure of SiO2(Si)&FexOy(Fe) with of SiO2 and FexOy matrices.•Mott’s or Efros-Shklovsky mechanisms of electron transport at low electric fields.•Space charge limited current at intermediate electric fields.•Electric field enhanced thermal activation of electron from the traps into conduction band (Poole-Frenkel mechanism) at highest electric fields. [Display omitted] In this study, electron transport mechanisms at a direct current in SiO2(Si)&FexOy(Fe) granular composite films containing Si and Fe nanoinclusions in the temperature range of 95–340 K were determined. The composite films were obtained by co-sputtering of Si and Fe targets in oxygen containing atmosphere (Ar+O2) followed by temperature annealing. It was found out that hopping conductivity with a variable-range hopping was realized at low electric fields. In the temperature range of 115<T<180 K, the electron transport could be reasonably described by the Efros-Shklovsky model taking into account the Coulomb interaction. At higher temperatures (180<T<340 K), the Mott model have been shown to be applicable. Using this model, a number of the characteristics of traps and transport process, namely the density of electron traps near the Fermi level, the activation energy of hopping, and the hopping length were determined. In the range of intermediate and high electric fields, the field enhanced thermal activation of electrons in the conduction band (Poole-Frenkel mechanism) was concluded. At this, the temperature independent current was obtained at the highest values of the electric field. This effect was explained by the influence of the energy position of electron traps taking part in the conductivity as well as the temperature dependence of a dielectric constant.