Thermal stability of hydrogen-doped AZO thin films for photovoltaic applications

Double doped zinc oxide films with aluminum and hydrogen were prepared by the radio frequency magnetron sputtering. The structural, electrical, and optical properties of the films were investigated in terms of the annealing conditions to study the thermal stability. The electrical resistivity was significantly increased when the films were annealed at higher temperature in air atmosphere. The optical transmittance of the films changed very little but the optical band gap was reduced. The grain in the film became larger while the degree of c-axis orientation was decreased by the heat treatment. Although the thermal stability of the double doped zinc oxide films was worse than that of the aluminum doped zinc oxide films, the efficiency of amorphous silicon thin films solar cells fabricated on double doped zinc oxide film was improved.