Study of ZnSxO1-x Prepared by Thermal Oxidation of ZnS Films Deposited from a Chemical Bath

Optical and structural characterization results of ZnS
_x
O
_1-x
films deposited by chemical bath deposition of ZnS with a subsequent thermal oxidation process are presented here. Varying annealing temperatures and times were used to incorporate different amounts of oxygen into the films. The band gap dependence on Sulfur (x) and Oxygen (1-x) composition in the ZnS
_x
O
_1-x
layers was studied. It is shown that the material in the films crystallizes in the hexagonal structure and a maximum oxygen concentration of 9 % is achieved, leading to a maximum energy bandgap reduction (increased affinity) of 0.27 eV which can be used to reduce unfavorable conduction band discontinuities at the ZnS/CIGS interface in solar cells.