Effect of Cu doping on structural and optical properties of II-VI binary compound semiconducting nanoparticles.

CdS and ZnS are important chalcogenides belonging to II-VI binary compound semiconductor which has wide applications in various optoelectronic devices, medical diagnosis and drug delivery system. The present work reports the synthesis of undoped and Cu doped CdS and ZnS nanoparticles by microwave assisted solvothermal method using the aqueous molar solution of cadmium acetate, zinc acetate, copper chloride and sodium sulphide. The structural properties of the as synthesized nanoparticles have been investigated via X-ray diffraction. The XRD spectrum confirms the crystallinity of the synthesized samples. The average crystal size of the nanoparticles was estimated via Scherrer equation and was found to be around 5.64 nm and 5.46 nm for undoped CdS and ZnS respectively and the value gets reduced on doping CdS and ZnS with Cu. The optical properties of the prepared nanoparticles were examined via PL and UV Visible spectra. The optical energy band gap of as synthesized nanoparticles was estimated using UV- Visible spectra via Tauc equation, which was found to be 3.80 eV and 3.70 eV for undoped CdS and ZnS respectively. The report shows the increment of the energy band gap of CdS and ZnS after doping it with Cu. [ABSTRACT FROM AUTHOR]