Chemical Bath Deposition of Zinc Sulfide Films Doped With Copper

Zinc sulfide (ZnS) films are doped with low copper concentrations by the chemical bath deposition (CBD) technique on glass substrates. The basic chemical bath contains ZnSO4, KOH, NH4NO3, and thiourea as chemical reagents. Different volumes of copper chloride solution (0.004 M) were included into the basic solution for doping. Doped films were deposited in a chemical solution at 363 K and deposition times from 30 to 90 min. The chemical solution and films present changes, from pale to dark-brown, in their color when the Cu doping is increased. The bandgap energy of the undoped and doped films ranged from 3.68 to 3.72 eV, meanwhile the crystalline structure suffers an amorphization with doping. The Cu-doped ZnS was verified with the photoluminescence technique.