Thin films can be used to fabricate optoelectronic devices. Technology is currently focusing on ternary thin film composition because of their structure, inter-band transitions and other optical properties that can be maximized. This book discusses in detail the optical characteristics of ternary thin films and further investigates the behavior of Iron Zinc Sulphide, Lead Silver Sulphide, Copper Silver Sulphide, Copper Zinc Sulphide and Cadmium Zinc Sulphide. Thin films are of fundamental importance in modern technology.