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ARTICLE

The effect of aluminum doping on nanostructured CdS: optical, structural and sensing characterization

H. R. Shakir^a, O. A. Chichan^b, M. S. Sada^c,*, S. A. Hussein^d, S. S. Chiad^e, N. F. Habubi^f, Y. H. Kadhim^g, M. Jadan^h,i

a Department of Optometry, Technical Medical Institute - Al-Mansur, Middle Technical University, Iraq.
b Department of Physics, College of Education for Pure Sciences, University of Babylon, Iraq.
c Department of Physics, College of Education, University of Masan, Iraq.
d Department of Medical Laboratory Techniques, Al-Manara College for Medical Science, Iraq
e Department of Physics, College of Education, Mustansiriyah University, Iraq.
f Department of Radiation and Sonar Technologies, Alnukhba University College, Iraq
g Department of Optics Techniques, College of Health and Medical Techniques, AL-Mustaqbal University, Babylon, Hillah, 51001, Iraq
h Department of Physics, College of Science, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, 31441 Dammam, Saudi Arabia
i Basic and Applied Scientific Research Center, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, 31441 Dammam, Saudi Arabia.

* Corresponding Author:

Chalcogenide Letters 2025, 22(1), 77-89. https://doi.org/10.15251/CL.2025.221.77

Received 08 November 2024; Accepted 17 January 2025;

Abstract

CdS, and CdS: Al were grown onto glass bases via Chemical spray pyrolysis (CSP). XRD analysis of CdS films indicates a polycrystalline hexagonal structure with a predominant orientation of the (101) plane. The strain decreased from 28.55 to 25.66, and the grain size of undoped CdS films was around (13.51–12.14) nm as Al content rose. According to the results of AFM, CdS, CdS:2% Al, and CdS:4% Al all exhibit smooth surfaces with decreasing particle size in the range of (78.46), (69.75), and (42.20) nm, respectively. The root-mean-square roughness values for CdS and CdS:4% Al were 12.41 nm and 3.38 nm. According to AFM image, the surface roughness of CdS to CdS:4% Al were (9.74-5.16) nm. SEM images depict CdS films transitioning from flat islands (Undoped CdS) to uniform spherical nano-grains with Al doping. The result shows a decrease in absorption coefficient as Al content increased. The optical bandgap increased from (2.35-2.51) eV after doping. Results show that the extinction coefficient and refractive index are influenced by Al content. CdS film detects NO₂ gas by resistance increase, impacted by Aluminum doping. Sensitivity decreases with an increase in Al doping in CdS films.

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Keywords

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