Effect of co doping to the optical properties of ZnO:Co Thin films deposited on glass substrate by sol-gel spray coating technique

Abstract

This study aims are to analyze the effect of cobalt doping concentration to the optical properties ZnO:Co thin films deposited by using sol-gel spray coating technique. Deposition of ZnO and ZnO:Co thin films has been successfully formed on a glass substrate using sol-gel method of spray coating technique with a variation of doping Co as much as 3%, 5%, 7%, 9%, and 11%. Solution of ZnO:Co synthesized by mixing zinc acetate dehydrate (Zn (COOCH3)2.2H2O into a isopropanol ((CH3)2CHOH) then monoethanolamine (MEA) and cobalt nitrate are added as a dopant at room temperature, then ZnO:Co sprayed on a glass substrate that has been heated at a temperature of 450°C. A thin film further characterized using spectrophotometer Uv-Vis to determine the value of absorbance and transmittance. Energy band gap was determined by using tauc plot that uses the absorbance value. The results show that there has been a difference in the value of the Energy band gap of ZnO with and without of Co doping. The addition of Co doping causes the decrease of small energy band gap. The magnitude of the energy band gap of thin films of ZnO is 3.337 eV and ZnO:Co 3% is 3.129 eV. Thin film that has narrower band gap was applied for material photocatalyst