Effect of the annealing process on electrical and optical properties of SnO2/Ag/SnO2 nanometric multilayer film

• The SnO2/Ag/SnO2 nano-multilayer structure has been designed and fabricated.
• High-quality films with sheet resistance of 4.4 Ω/sq were obtained.
• The allowed direct band gap decreases with increasing substrate temperature.
• The band structure and conductive mechanism of the SAS films were discussed.

The SnO2/Ag/SnO2 nano-multilayer structure has been designed and fabricated on quartz glass by magnetron sputtering and then annealed in air. The effect of annealing temperature on the structural, optical, and electrical properties of the SAS films was investigated. The SEM images and XRD patterns show that crystallinity of the samples was improved as a result of annealing. High-quality transparent conductive films with sheet resistance of 4.4 Ω/sq and maximum transmittance of 91% at 500 nm wavelength were obtained with an annealing temperature of 200 °C. The figure of merit of the SAS films annealed at 200 °C reached a maximum of 3.39×10−2 Ω−1. It is observed the allowed direct band gap decreases with increasing substrate temperature. These multilayer films can be used as transparent conductive electrodes in optoelectronic devices.