Growth of Cu(In,Ga)Se2 thin films using ionization Ga source and application for solar cells

Cu(In, Ga)Se2(CIGS) thin films with lower (GA/III = 0.30) and higher (Ga/III 0.70) Ga-content were grown onto the soda-lime glass substrates by the co-evaporation process using ionization Ga source. The enlargement of grain size for the as grown CIGS films was observed using the higher-grid ionization voltage, (V-c) and filament current (I-fila). XRD results revealed that the crystal quality can be improved using higher Ve and Ifila which is consistent with SEM results. Hall effect measurements showed that an obvioius increasing in Garner concentration and decreasing in resistivity using higher Vc. Finally the lower and higher Ga-content CIGS solar cell with a promising efficiency of 15.4% and 8.27% has been achieved, respectively. Our results suggested that the high energy ingerent to the ionized Ga atoms could be transferred to the substrate and played an important role for improvement of film quality like a local substrate heating sources.