Preparation of Cu(In,Ga)Se2 layers by selenization of electrodeposited Cu–In–Ga precursors

The Cu–In–Ga layers with various Ga-content were produced from one bath by electrodeposition on molybdenum substrates. The use of complex thiocyanate electrolyte allows for a remarkable shift of the deposition potential of elemental copper to the deposition potentials of indium and gallium. The influence of different deposition conditions on film properties was investigated and the possibility of reproducible Cu–In–Ga precursor layer deposition with good composition control was demonstrated. The Cu–In–Ga precursors were selenized in a quartz tube furnace at 560 °C under the selenium pressure of 10 mbar. Cross-sectional energy dispersive X-ray analysis (EDX) line scan measurements showed an accumulation of Ga towards the Mo back contact. The best solar cell structures on the base of selenized Cu(In,Ga)Se2 (CIGS) thin film gave the photoconversion efficiency of 4%.