Optoelectronic and structural properties of multilayer oxide/silver/oxide transparent conducting electrodes using green laser annealing

Abstract

Transparent conducting ITO/Ag/ITO (IAI) and AZO/Ag/AZO (ZAZ) multilayer electrodes were fabricated using radio frequency magnetron sputtering at room temperature. Subsequently, a green laser was employed for annealing these multilayer films to improve their optical, electrical, and structural properties. Their optical and electrical properties were characterized using a UV–Vis spectrophotometer, and a four-point probe station, respectively, while structural properties were characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM). After laser annealing, XRD analysis indicated an increase in Ag intensity peak, correlating with larger crystallite size post-annealing. TEM analysis confirmed the formation of a continuous structure as weakly connected Ag crystallites bonded during the annealing process. The IAI electrodes showed significant improvement, reducing sheet resistance from 8.2 Ω/sq to 6.9 Ω/sq, and the Haacke index improved from ϕ_Vis ≈ 17 × 10⁻³ Ω⁻¹ to ϕ_Vis ≈ 21 × 10⁻³ Ω⁻¹. In contrast, the physical properties of the ZAZ electrodes could not be further improved by the laser annealing process, as their Ag layers already exhibited high crystallinity. Our results indicate that optimizing the conductivity of the Ag layer is crucial for the optoelectronic performance of multilayer electrodes. This optimization can be achieved through laser annealing with suitable energy densities and using oxide layers promoting dense Ag growth.