Characterization of CIGS thin films and solar cells grown with a plasma-cracked Se source

The variation observed in rf-plasma cracked radical Se (R-Se) source grown Cu(In, Ga)Se₂ (CIGS) film properties and conventional evaporative Se (E-Se) source grown CIGS film properties was studied for the development of industrial production techniques of evaporated CIGS films and CIGS texture control techniques, which are important for the optimization of the CIGS/buffer layer interface to yield high cell and module efficiencies using various types of buffer layer materials as well as for the study of surface and interface physics of CIGS solar cells. R-Se grown CIGS films exhibit distinctive characteristics such as highly dense surfaces and large grain size in comparison with E-Se grown CIGS films. On the other hand, R-Se grown (In, Ga)₂Se₃ precursor films was similar to E-Se grown films fabricated with the Se to metal flux ratio (P_[Se]/[In+Ga]) of around 6, though the nominal P_[Se]/[In+Ga] used for a R-Se source was less than 0.5, implying that the use of a R-Se source can demonstrate a significant reduction of the raw material consumption of Se. In the present work, it is shown that the Se source conditions used for the CIGS growth have a variety of important effects on the growth kinetics and concomitant solar cell properties.