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<p>The present investigation explores the effect of Fe<sub>2</sub>O<sub>3</sub> incorporation into a vanadium-based multi-component oxide matrix, focusing on the resulting microstructural modifications, electrical transport properties, and dielectric performance of amorphous semiconducting nanocomposites. Powder x-ray diffraction studies reveal the coexistence of multiple nanocrystalline phases within the amorphous host, indicating the development of polycrystalline characteristics in the synthesized materials. The comparatively high Debye temperature values signify enhanced thermal stability of the system. Optical studies suggest the occurrence of indirect allowed electronic transitions, while the estimated optical band gap values support charge transport through a non-adiabatic small-polaron hopping mechanism. Among all investigated compositions, the sample with <i>x</i> = 0.2 exhibits the minimum relaxation time of 0.95891 × 10<sup>−14</sup>&#xa0;s, together with the highest concentration of localized states near the Fermi level. The density of states is estimated to be 4.77 × 10<sup>18</sup> eV<sup>−1</sup>&#xa0;cm<sup>−3</sup> at lower temperatures, based on Mott’s variable range hopping model, and 3.89 × 10<sup>28</sup> eV<sup>−1</sup>&#xa0;cm<sup>−3</sup> at higher temperatures, using Greaves’ formalism. These factors collectively contribute to the enhancement of DC electrical conductivity dominated by polaron-assisted carrier transport. Compared with earlier reported Fe<sub>2</sub>O<sub>3</sub>-containing oxide systems, the <i>x</i> = 0.2 composition demonstrates superior dielectric characteristics and improved carrier mobility, highlighting its suitability for high-power laser and advanced optoelectronic applications. Furthermore, the unusual variation of relaxation time with temperature indicates faster charge-carrier dynamics, whereas the analysis of Kohlrausch–Williams–Watts parameters reveals a progressive transition from non-Debye to Debye-type relaxation behavior with increasing Fe<sub>2</sub>O<sub>3</sub> concentration. Overall, the study provides deeper insight into composition-dependent conduction and relaxation phenomena, offering valuable directions for the design and optimization of high-performance functional nanocomposite materials.</p> Graphical Abstract <p></p>

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Polaron Hopping Phenomena in TMI-Doped Nanocomposite Systems: Mixed Polaron Effect (MPE) in Physical, Structural, Electrical, and Dielectric Properties

  • 期刊论文

  • 发表日期：

    2026年6月23日

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  • Jiban Ghosh,
  • Mir Sahidul Ali,
  • Dipankar Chattopadhyay,
  • Ritu Sarkar,
  • R. K. Shukla,
  • Joydeep Chowdhury,
  • Sanjib Bhattacharya

摘要

The present investigation explores the effect of Fe2O3 incorporation into a vanadium-based multi-component oxide matrix, focusing on the resulting microstructural modifications, electrical transport properties, and dielectric performance of amorphous semiconducting nanocomposites. Powder x-ray diffraction studies reveal the coexistence of multiple nanocrystalline phases within the amorphous host, indicating the development of polycrystalline characteristics in the synthesized materials. The comparatively high Debye temperature values signify enhanced thermal stability of the system. Optical studies suggest the occurrence of indirect allowed electronic transitions, while the estimated optical band gap values support charge transport through a non-adiabatic small-polaron hopping mechanism. Among all investigated compositions, the sample with x = 0.2 exhibits the minimum relaxation time of 0.95891 × 10−14 s, together with the highest concentration of localized states near the Fermi level. The density of states is estimated to be 4.77 × 1018 eV−1 cm−3 at lower temperatures, based on Mott’s variable range hopping model, and 3.89 × 1028 eV−1 cm−3 at higher temperatures, using Greaves’ formalism. These factors collectively contribute to the enhancement of DC electrical conductivity dominated by polaron-assisted carrier transport. Compared with earlier reported Fe2O3-containing oxide systems, the x = 0.2 composition demonstrates superior dielectric characteristics and improved carrier mobility, highlighting its suitability for high-power laser and advanced optoelectronic applications. Furthermore, the unusual variation of relaxation time with temperature indicates faster charge-carrier dynamics, whereas the analysis of Kohlrausch–Williams–Watts parameters reveals a progressive transition from non-Debye to Debye-type relaxation behavior with increasing Fe2O3 concentration. Overall, the study provides deeper insight into composition-dependent conduction and relaxation phenomena, offering valuable directions for the design and optimization of high-performance functional nanocomposite materials.

Graphical Abstract