Effects of sulfur introduction on the UV and the visible emission properties of ZnO

Hexagonal ZnO particles have been synthesized by using the hydrothermal method with different sulfur concentrations in the reaction solutions. Structural and optical characterizations have been conducted to study the effects of the sulfur in the reaction solutions on the properties of the synthesized ZnO in the ultraviolet (UV) and the visible (VIS) bands. The existance of sulfur in the solutions can help to introduce compression strain along the a axis and an opposite trend for the parameter c with strain inside the formed ZnO particles, which means the total strain in the samples is presented along the c axis. The average size of the ZnO particles, as calculated from SEM images, shows the same trend as the strain in the samples. The increasing incorporation of sulfur causes an increase in the VIS luminescence band, which can be attributed to an increase in the number of sulfur-induced defects.