Er-doped ZnS QDs like NPs for optoelectronic applications: a facile microwave-assisted synthesis

Er-doped zinc sulfide nanoparticles are successfully achieved by the microwave-assisted coprecipitation route. XRD and Raman studies confirm the crystalline nanogrowth of the prepared nanostructures. The stress–strain analyses of the samples were made using Williamsons–Hall (UDM, USDM, and UDEDM) plots. The Raman bands at 257 and 340 cm⁻¹ are associated with the transverse optic (TO) and longitudinal optic (LO) phonon modes of ZnS. SEM/EDX/SEM e-mapping micrographs and compositional analyses approve the formation of nanoscale materials with proper elemental composition and homogeneity. The band gap values of the prepared samples were estimated in the range of 3.61–3.64 eV using the Kubelka–Munk plots derived from the experimental diffuse reflectance data. The photoluminescence spectra of Er-doped ZnS nanoparticles were studied at 320 nm and 400 nm excitation wavelengths. The emission peaks of 320 nm excitation were observed at 364 nm, 380 nm, 423 nm, 438 nm, and 520 nm. The dielectric values are found within the range of 15–23 in the frequency range of 1 kHz–10 MHz, which are slightly lower compared to pure ZnS nanoparticles in the same range, and the reason is attributed to the effects of Er doping.