Authors

Tawfik Mahmood Mohammed Ali

Department of Physics, Faculty of Education, University of Aden, Yemen

Sarah. M. Al-Khadher

Department of Physics, Faculty of Education-Saber, University of Aden, Yemen

M. A. Dabban

Department of Physics, Faculty of Science, University of Aden, Yemen & Department of Health Science, Faculty of Medicine and Health Science, University of Science & Technology, Yemen

Abstract

In this work, the structural, morphological, optical, and electronic properties of Ge20Cd10Se70 thin films were systematically investigated as a function of thickness (400-1000 nm). Energy dispersive X-ray (EDAX) analysis confirmed the stoichiometric composition and purity of the films, while X-ray diffraction (XRD) revealed the emergence of Se, GeSe2, CdSe, and Cd4GeSe6 phases at higher thicknesses, indicating an amorphous-to-crystalline transition. SEM and AFM confirmed improved crystallinity, with crystallite size increasing (14.27 to 41.87 nm) as strain and defect density decreased. Optical measurements (200–2500 nm) showed that transmittance and reflectance varied with thickness, while both the extinction coefficient and refractive index decreased with increasing wavelength but increased with thickness. The optical band gap decreased, and the band tail width increased with thickness, consistent with Mott and Davis’s model. Dispersion analysis using the Wemple–DiDomenico model indicated enhanced atomic packing, with oscillator energy decreasing and dispersion energy increasing as thickness grew. Thickness also strongly influenced dielectric constants, carrier concentration to effective mass ratio, susceptibility, nonlinear refractive index, and the electronic parameters such as plasma frequency, Penn energy, Fermi level, electronic polarizability, and molar refractivity. These results confirm that controlled thickness tailoring enables Ge20Cd10Se70 thin films to exhibit tunable optoelectronic behavior, making them promising materials for optoelectronic devices.

Keywords

Ge–Cd–Se thin films; Thickness-dependent properties; Morphological analysis; Optical band gap tuning; nonlinear optical parameters electronic polarizability

Citation of this Article

Tawfik Mahmood Mohammed Ali, Sarah. M. Al-Khadher, & M. A. Dabban. (2025). Thickness-Dependent Structural, Morphological, Optical, and Electronic Properties of Ge20Cd10Se70 Thin Films for Optoelectronic Applications. International Current Journal of Engineering and Science (ICJES), 4(11), 55-86. Article DOI: https://doi.org/10.47001/ICJES/2025.411010

Licence Copyright (c) 2026 International Current Journal of Engineering and Science. This work is licensed under a Creative Commons Attribution Non Commercial 4.0 International Licence.

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