Fabrication of Copper Arsenic Sulfide Thin Films from Nanoparticles for Application in Solar Cells

Thin films of copper arsenic sulfide (Cu
₃
AsS
₄
) have been fabricated for the first time by annealing nanoparticles in an arsenic (V) sulfide atmosphere. The resulting films contained dense, micron-sized grains when treated at 425 °C, with the crystal structure transforming from the tetragonal luzonite phase to the orthorhombic energite phase and an amorphous impurity phase appearing in the Raman spectrum. Solar cells were fabricated using CdS as the n-type buffer layer, yielding device efficiencies up to 0.24%.