Synthesis, structural, optical, and dielectric properties of novel barium-doped bismuth selenide

This paper reports about the first time doping of bismuth selenide with barium (x = 0, 0.03, 0.09, 0.12, and 0.15) via Sol–Gel route to investigate the structural, optical, and dielectric properties using X-ray diffraction, UV–Vis spectroscopy, Photoluminescence, FTIR, and dielectric measurements. Structural analysis of synthesized samples using XRD proved that the samples possess crystalline nature and orthorhombic structure. The crystallite size of pure Bismuth selenide is about 20.04 nm. The crystallite size of samples with 3%, 9%, 12%, and 15% doping concentration is about 32.74 nm, 24.91 nm, 32.25 nm, and 33.38 nm, respectively. This shows that crystallite size increases with increase in doping concentration. The FTIR spectra exhibit that the wavenumber corresponding to 600–430 cm−1 represents the Bi–Se stretching vibrations, whereas wavenumber 729 cm−1 in doped corresponds to the Ba–N bond. UV–Vis analysis shows that the band gap of pure sample is about 2.56 eV. The band gap of sample with x = 0.03, 0.09, 0.12, and 0.15 is 2.39 eV, 2.25 eV, 1.66 eV, and 1.48 eV, respectively. Dielectric parameters including dielectric constant, dielectric loss, AC electrical conductivity, and impedance varied with frequency were also measured. These results showed that Barium-doped Bismuth Selenide nanomaterials are suitable for high-frequency applications.