Cu(In,Ga)Se2 hybrid sputtering/evaporation deposition for thin film solar cells application

CuInSe2-based solar cells showed long-term stability and the highest conversion efficiencies among thin film solar cells, overcoming 20%. The optoelectronic properties of the absorber layers and interfaces are strongly dependent upon the deposition method and strictly related to the solar cell efficiency. In this work, an alternative approach for CIGS thin film growth has been developed and tested. Such approach consists of sputtering deposition of the metal elements combined with selenium co-evaporation, which allows deposition time of the CIGS layer lower than 30 min, matching industrial application requirements. The relationships between the growth parameters of such hybrid sputtering/evaporation method and the chemical-physical properties of the CIGS films have been studied. The CIGS cell performances have been monitored by External Quantum Efficiency measurements and I-V measurements. Test solar cells of 0.5 cm2 have shown an efficiency of 14 % on glass substrates.