Photoelectric Characteristics of Trilayer Thin-film Structures Processed at Different Annealing Temperatures for Photosensors

Radio frequency (RF) magnetron sputtering was used to sputter a thin layer of ITO:Ga with a purity of 97:3 at% on glass substrates. A layer of Zr with a purity of 99.99% was then deposited on the ITO:Ga layer by direct current magnetron sputtering. Finally, RF magnetron sputtering was used once again to deposit a thin ZnO layer with a purity of 99.99 at% on top of the Zr layer. The three-layered film structure was annealed in a vacuum at various temperatures in the range of 200–500 °C in order to prompt a rearrangement of the crystal structure and reduce the number of internal defects. The effects of the annealing temperature on the film thickness, electrical properties, optical properties, surface morphologies, and quality factors of the multilayered films were investigated. The trilayer film showed a minimum resistivity of 1.79 × 10−3 Ω-cm after annealing at a temperature of 500 °C and an average optical transmission of 88.14% after annealing at 300 °C. The optimal quality factor (1.44 × 10−3 Ω−1) was obtained for the film annealed at 500 °C.