Synthesis and characterization of egg-like cadmium sulphide nanoparticles grown by hydrothermal method

CdS is one of the most important members of the metal chalcogenide family that exists as two different polymorphs, hexagonal, cubic or mixture from them but hexagonal form is the common form of CdS with a band gap of 2.4 ev[1]. Therefore, it was playing an important role in opto- electronic devices such as multilayer light emitting diodes, phototransistors, the window layer in hetero- junction solar cells and so on[4]. In this present paper, egg-like CdS nanoparticles have been synthesized by hydrothermal method in 150°C for 48 h using Cd(NO3)2∙4H2O and thiourea as raw materials and NH4OH as a complexing agent. The obtained product was characterized by XRD,SEM, EDX and DRS techniques. XRD pattern confirms the formation of hexagonal structure of CdS with average grain size of 36 nm(Fig.1). EDX spectrum demonstrate that the products are well crystallized with high purity. SEM images depict the presence of egg-like nanoparticles in the sample with a diameter range of 50 nm (Fig.2). From DRS spectrum of CdS nanoparticles of our present study(Fig.3), a well-defined absorption peak at 480 nm is observed. The exciton absorption observed at about 480 nm, which is blue shifted compared with the characteristic absorption of bulk CdS may be due to quantum confinement effects.