CZGS films with different Cu contents were prepared by sputtering method.
Cu-rich films exhibit large grain size compared to those of Cu-poor films.
Square resistance decrease from 14.2 to 1.3 k惟/鈻?with increasing grain size.
Band gaps of the films decrease from 1.97 eV to 1.80 eV as Cu content increases.
Reason for diverse values of Eg of CZGS based on the band theory is discussed.