“…As n-type semiconductors with a large and variable bandgap between 2.42 and 3.54 eV, the ternary Cd 1 À x Zn x S compounds have been used as a window layer to form heterojunction solar cells with Si [1], Cu x S [2], CuInSe 2 [3], CuGaSe 2 [4], Cu(In, Ga)Se 2 (CIGS) [5] and CdTe [6]. For commercial CdS/CdTe and CdS/CIGS solar cells, CdS is the standard window layer despite its relatively low bandgap (2.42 eV) and considerable absorption in the short wavelength region (below 500 nm).…”