Fabrication of ZnS thin films by an improved photochemical deposition method and application to ZnS/SnS heterojunction cells

ZnS films were deposited from aqueous solutions containing S2O32− ions and Zn2+ ions by photochemical reactions. S2O32− ions release sulfur in an acidic solution, but if the released sulfur is excess, sulfur colloids are formed. To prevent the colloid formation, Na2SO3 was added for trapping of the excess sulfur. The deposited films were nearly stoichiometric and had photosensitivity. In order to fabricate ZnS/SnS heterojunction cells, ZnS was deposited on p-type SnS thin films deposited by the electrochemical deposition method. In a current–voltage measurement, the heterojunction cells showed rectification properties.