Investigations of optical and dielectric properties of thermally stable manganese-doped zinc telluride quantum dots for insulator and optical data storage applications

The research discussions presented here emphasise the analysis of dielectric properties of the undoped and manganese (Mn)-doped zinc telluride (ZnTe) quantum dots (QDs) by studying the capacitance, AC conductivity, dielectric constant and dielectric loss with respect to frequency. The capacitance of the mentioned QDs is found to increase with an increase in the manganese concentration. The AC conductivity and dielectric loss are observed to be less in manganese-doped ZnTe QDs. Such QDs can be employed for applications of insulating materials. The Differential Scanning Calorimeter study reveals the reduced melting when Mn is doped into ZnTe, illustrating the increased surface-to-volume ratio. Thermal stability measurement using thermogravimetric analysis (TGA) shows that the decomposition of the QDs due to Zn between 320°C and 400°C can be reduced when Mn is incorporated. From the optical studies, the loss in the absorption of light is observed in Mn-doped ZnTe QDs, indicating possible trapping of the photons in F-centre-like defects. At the higher wavelength in all the synthesised QDs, the refractive index remains constant at higher wavelength, making these QDs suitable for optical data storage device applications.