Mn1−xSnxTe composite nanocubes synthesized by hydrothermal method for optoelectronic and dielectric applications

Abstract

The dielectric materials based on Mn-Sn-Te are in demand for their unique properties like minimum loss, satisfactory temperature stability, and extensive energy storage capability. The present work reports on the alterations in structural, optical, and dielectric characteristics of Mn_1−xSn_xTe (0.1, 0.25, 0.5, 0.75, and 0.9) composite by the variation in Mn and Sn content, which were synthesized by single-step hydrothermal method. The X-ray diffraction study confirmed the cubic form of the crystallites with a decrease in crystallite size from 71 nm to 23 nm, whereas the dislocation and strain values increased as the Mn amount decreased in the composition. The presence of two polycrystalline phases, MnTe and SnTe, was observed from the Raman analysis. The TEM analysis confirmed the presence of these two phases with a lattice spacing of 1.58 Å for the SnTe (400) and 1.30 Å for the MnTe (144) plane. Large reflectance was found from the high Mn content sample, and these samples exhibit low bandgap values, which decreased from 0.63 eV to 0.41 eV with a decrease in Mn content. The refractive index increased from 3.86 to 4.35 with the decrease in Mn content. The morphological analysis through FESEM showed the nanocubes. The EDX study showed the presence of all the constituent elements in the synthesized samples, which was also supported by the XPS analysis. The dielectric constant and AC conductivity were found to be more at higher temperatures. The prepared sample showed a maximum dielectric constant of 339,435 for 400 °C sample at 1 KHz frequency. Applications for electronic and energy storage devices may benefit from the SnMnS matrix's aforementioned optical, electrical, and dielectric characteristics.