Effect of ammonia on the structural, morphological and optical properties of nanocrystalline ZnS thin film

Abstract

Zinc sulphide (ZnS) is a semiconductor used extensively in optoelectronic devices. It is frequently used as a buffer layer in highly efficient solar cells due to its ecologically favourable qualities. In this work, we have studied the effect of ammonia during the synthesis of ZnS thin film using the chemical bath deposition (CBD) method for optical properties. The CBD route uses metal ions so that there are no hydroxide products, and the deposition process occurs in the ion-by-ion process. The formation of the ZnS thin films has been examined by x-ray diffraction. The resulting films contain a polycrystalline structure, a cubic and hexagonal mixture, and a strong preference for orientation along the (111) plane of the main cubic phase. The SEM and TEM images have shown the effect of ammonia on grain size, and both types of films have a thick, homogenous surface morphology. The optical properties of ZnS thin films with NH3 were better than without, determined by UV/Vis spectroscopy. Among all synthesized materials, ZnS thin film with NH3 and without stirring exhibits the highest optical quality and film crystallization. The obtained results indicated that it is optimistic in optoelectronics and photovoltaic applications.