Proceedings of International Conference on Applied Innovation in IT
2026/03/31, Volume 14, Issue 1, pp.495-502
Data-Driven Gas Sensing Performance of Cu-Doped ZnO Thin Films
Abdul-Lateef Abdul-Jabar, Mushtaq Talib Hamzah, Rabab Mohammed Habeeb, Muhaned Zaidi and Saja Faez Hassan Abstract: This work systematically investigates the effect of Cu doping on the properties of ZnO thin films deposited onto glass substrates via chemical spray pyrolysis (CSP) at 450 °C. A series of undoped films, as well as films doped with 1% and 3% Cu, were synthesized and comprehensively characterized. Structural analysis by XRD verified that all films exhibited a polycrystalline nature with a hexagonal wurtzite structure, demonstrating a growth orientation along the (002) plane. The crystallite size increased from 14.32 nm for ZnO to 25.36 nm (3% Cu), indicating an enhancement in crystallinity. This was supported by a concurrent decrease in dislocation density and microstrain. Atomic force microscopy (AFM) showed that Cu doping significantly reduced surface roughness and average grain size, resulting in smoother and more compact films. Optically, increasing the Cu content resulted in lower visible light transmittance and a higher absorption coefficient. The optical bandgap energy red-shifted from 3.50 eV for ZnO to 3.40 eV for the 3% Cu-doped sample. In gas sensing tests, the 3% Cu-doped film exhibited the highest sensitivity to ammonia (NH₃) due to an increase in electrical resistance. Conversely, sensitivity to hydrogen (H₂) decreased with higher Cu doping levels. The findings conclusively demonstrate that strategic copper doping serves as a controllable method for engineering the properties discussed in this paper, thereby optimizing them for targeted device applications.
Keywords: ZnO, Copper Doping, Thin Films, CSP, XRD, AFM, Optical Properties, Gas Sensing.
DOI: Under indexing
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