With the exception of HgSe and HgTe, II-VI compounds are direct gap se
miconductors with sharp optical absorption edge and large absorption c
oefficients at above bandgap wavelengths. Device quality polycrystalli
ne films of II-VI compounds can be prepared from inexpensive raw mater
ials by a number of low-cost methods. They are well-suited for thin fi
lm solar cells and provide an economically viable approach to the terr
estrial utilization of solar energy. Thin him II-VI solar cells are us
ually of the heterojunction type consisting of a high bandgap window (
or collector) and a lower bandgap absorber. The grain boundary effects
in polycrystalline II-VI films are considerably less pronounced than
those in III-V films and can be passivated, at least partially, by che
mical treatment. The use of CdS, ZnO, ZnSe and Cd1-xZnxS as the window
and the use of CdTe and Cd1-xZnxTe as the absorber are reviewed in th
is paper. The fabrication and characteristics of a number of the thin
film solar cell structures are discussed with emphasis on the thin fil
m CdS/CdTe solar cell.