Dielectric Constant, Metallization Criterion and Optical Properties of CuO Doped TeO2–B2O3 Glasses

Copper oxide doped TeO2–B2O3 glass system with empirical formula; $${[\left({{\text{B}}_{2}{\text{O}}_{3})}_{0.3}{\left({\text{TeO}}_{2}\right)}_{0.7}\right]}_{1-x}{(\text{CuO})}_{x}$$ was fabricated using the melt quenching method, where x = 0.0, 0.01, 0.015, 0.02, and 0.025 was combined. The glass samples’ density and molar volume were measured, followed by characterizations using the UV–Vis, Fourier transform infrared (FTIR), and X-ray diffraction (XRD) spectroscopes. The amorphous or glassy nature of glass samples was proven by the XRD spectra except for the pure borotellurite sample which showed a peak around 2θ = 20°, indicating α-TeO2 crystalline phase presence. The FTIR spectral analysis suggested the presence of BO3, TeO3, and TeO4 as the structural units in the glass samples. The UV–Vis spectra showed no presence of any sharply defined edges, affirming the amorphous or glassy nature of the glass materials. Physical parameters e.g. molar volume, density, oxygen packing density (OPD), the interionic distance of Cu2+ ions, the concentration of copper ion per unit volume (N), as well as the polaron radius data were presented and discussed. Also, the direct bandgap (3.8900 to 3.5900 eV), indirect bandgap (3.3200 to 3.0800 eV), refractive index (2.318 to 2.378), dielectric constant (5.3731 to 5.6549), optical dielectric constant (4.3731 to 4.6549), refractive index based metallization criterion (0.406885 to 0.391916) and the bandgap based metallization criterion (0.407431 to 0.392428) were analyzed and discussed. Based on the metallization criterion and values of the refractive index, the glasses are good candidates for optoelectronic and laser applications. Meanwhile, the dielectric constants’ values of the present glasses indicate their suitability bandpass filters and microelectronic substrates applications.