Effect of deposition and annealing parameters on the properties of electrodeposited CuIn1−xGaxSe2 thin films

CuIn1−xGaxSe2 thin films were prepared by one step electrodeposition from reagents CuSO4, In2(SO4)3, SeO2 and Ga2(SO4)3. The influence of deposition parameters (electrolyte composition, concentration of reagent and deposition potential) on film composition was studied. The structure, composition, morphology, optical and electrical properties of as-deposited and of annealed films were investigated. The X-ray diffraction analysis showed that the films annealed above 350 °C have a chalcopyrite structure of CuInSe2. The concentration of In2(SO4)3 affects the composition of In and Se in the films. The optical band gap of the films was varied between 1.01 and 1.26 eV by increasing the Ga content in the films. The electrical resistivity of CIS at room temperature decreased down to 10 Ω cm. The conduction mechanism in the CIS films was investigated in the temperature range 150 to 350 K.