Abstract
This study aimed to synthesize copper oxide (CuO) thin films using an eco-friendly green synthetic approach. A sol-gel spin coating technique was employed for the synthesis of the CuO thin film using Allium cepa as a reducing agent. The fabricated CuO thin film was investigated using the Fourier Transform-Infrared (FTIR) spectroscopy, Ultraviolet-visible spectra studies (UV-Vis), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and the Four-Point Probe measurement. The SEM micrographs revealed that the particles were spherically shaped, while the EDX analysis revealed that the CuO thin film was composed of copper and oxygen elements. Furthermore, the XRD analysis confirmed the monoclinic crystalline structure of the CuO thin film, while the FTIR spectroscopy investigated the chemical bonds formed during the production process. Contrarily, the UV-Vis spectroscopy reported a strong absorption of the film at the visible spectra with an estimated optical energy band gap of 1.48 eV. The electrical analysis, however, disclosed that the synthesized thin film portrayed good semiconducting behaviors.
Highlights
Copper (Cu), being a 3d transition metal, possesses impressive physicochemical qualities; due to its fundamental instability, copper thin films are liable to surface oxidation when exposed to the surrounding atmosphere at room temperature
composed of two popular oxides: tenorite (CuO) which is a semiconducting compound located in group I-IV of the periodic table, has over the years been of much interest as a result of the electrical and optical properties it possesses [2]
The purchased chemicals were all procured from Sigma-Aldrich, and they were used as received without subjection to any more purification
Summary
Copper (Cu), being a 3d transition metal, possesses impressive physicochemical qualities; due to its fundamental instability, copper thin films are liable to surface oxidation when exposed to the surrounding atmosphere at room temperature. This leads to the fabrication of copper oxides [1]. Copper oxides (Cu2O) have been researched as semiconductors for multiple reasons, which include the natural abundance of starting material copper; its simplicity of production by the oxidation of Cu; its non-hazardous nature; and its remarkably excellent optical and electrical properties by Cu2O [2]. As a result of its powerful solar absorbance and minimal thermal emittance [9], CuO has been acknowledged to be an attractive solar absorber, while Cu2O is a very favorable option for solar cell applications due to its suitability for photovoltaic energy conversion [10,11]
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