Geometry-Induced Electric Field Enhancement in Planar and Radial Si/GaAs Heterojunctions Under Incomplete Ionization

  • J.Sh. Abdullayev Institute of Fundamental and Applied Research, National Research University “TIIAME”, Tashkent, Uzbekistan; National Research University TIIAME, Department of Physics and Chemistry, Tashkent, Uzbekistan https://orcid.org/0000-0001-6110-6616
  • B. Uralov National Research University TIIAME, Department of Physics and Chemistry, Tashkent, Uzbekistan https://orcid.org/0000-0001-9371-5563
  • M.Sh. Ibragimova Urgench State University, Urgench, Uzbekistan https://orcid.org/0009-0004-7867-7086
  • B. Tadjibaev Tashkent State Technical University, Tashkent, Uzbekistan
  • M.F. Atayeva Bukhara State University, Bukhara, Uzbekistan
  • G. Boymurodov Navoi State University of Mining and Technologies, Navoi, Uzbekistan
  • S.Y. Yusupov Department of Traumatology and Neurosurgery, Bukhara State Medical Institute, Bukhara, Uzbekistan
DOI: https://doi.org/10.26565/2312-4334-2026-3-47
Keywords: Si/GaAs heterojunctions, Field distribution, Incomplete dopant ionization, Cryogenic temperatures, Depletion region

Abstract

This work presents a comprehensive electrostatic and transport analysis of planar and radial Si/GaAs heterojunctions over the cryogenic-to-room-temperature regime (20–300 K) using self-consistent solutions of the Poisson and carrier continuity equations implemented within advanced semiconductor device simulation frameworks. Particular emphasis is placed on the role of incomplete dopant ionization and its coupling with junction geometry in determining electric-field distribution and carrier transport characteristics. The results demonstrate that incomplete ionization significantly alters the electrostatic behavior of the heterojunctions at cryogenic temperatures, whereas its influence progressively diminishes near room temperature due to enhanced dopant activation. For planar heterojunctions under complete ionization, the maximum electric field decreases from approximately 1.55∙103 V/cm at 20 K to 8.5∙102 V/cm at 300 K. Incorporation of incomplete ionization reduces the peak field by nearly 50–100 V/cm below 50 K, while producing negligible deviations above 200 K. In contrast, radial heterojunctions exhibit pronounced electric-field localization arising from curvature-induced geometric confinement. Under incomplete ionization, the peak electric field remains within 3.2∙104–3.6∙104 V/cm, increasing to 4.2∙104–4.6∙104 V/cm for fully activated dopants, corresponding to a geometry-enhanced field amplification of approximately 28–38%. Carrier transport analysis further reveals strong temperature sensitivity of minority carrier injection, which increases by nearly seven orders of magnitude, from 102 cm-3 at 50 K to 109 cm-3 at 300 K, whereas majority carrier concentration remains nearly constant at 1016 cm-3. The radial architecture additionally produces localized depletion-field enhancement near the cylindrical interface, indicating superior electrostatic confinement compared with conventional planar configurations. These findings establish the coupled influence of geometry, dopant activation, and temperature-dependent transport mechanisms on Si/GaAs heterojunction performance and provide a rigorous framework for the optimization of cryogenic optoelectronic, nanoelectronic, and high-field semiconductor devices.

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Published
2026-09-07
Cited
How to Cite
Abdullayev, J., Uralov, B., Ibragimova, M., Tadjibaev, B., Atayeva, M., Boymurodov, G., & Yusupov, S. (2026). Geometry-Induced Electric Field Enhancement in Planar and Radial Si/GaAs Heterojunctions Under Incomplete Ionization. East European Journal of Physics, (3), 516-525. https://doi.org/10.26565/2312-4334-2026-3-47
Issue
No. 3 (2026): East European Journal of Physics
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Original Papers

Copyright (c) 2026 J.Sh. Abdullayev, B. Uralov, M.Sh. Ibragimova, B. Tadjibaev, M.F. Atayeva, G. Boymurodov, S. Y. Yusupov

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