Band-gap Control of Nanostructured CuO Thin Films using PEG as a Surfactant

Nanostructured copper oxide thin films were fabricated on glass substrates at room temperature by a facile and costefficientSuccessive Ionic Layer Adsorption and Reaction (SILAR) method with varied amounts of polyethylene glycol(PEG). The effects of PEG on the optical properties of the CuO thin films were investigated by means of ultravioletvisible(UV-Vis) spectroscopy analysis. By UV–Vis analysis at the room temperature, it was seen that the optical bandgap values and transmission characteristics of the CuO thin films vary with the increasing PEG concentration in thegrowth solution. The optical band gap energy of the CuO thin films was found to increase from 1.30 eV to 1.42 eV withthe increasing PEG concentration. The thickness of the CuO thin films was also found to vary in between 137 nm and680 nm depending on the PEG concentration. Other significant parameters including refractive index (n), high frequencydielectric constant () and optical static (0) values of the thin films were calculated by using the optical band gap energyvalues as a function of the film thickness. The investigations revealed that the PEG concentration has a remarkable impacton the optical properties of SILAR grown CuO thin films.

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