Thermal stability enhancement of ultrathin Ag film electrodes by incorporating atomic oxygen

• Published in: Applied surface science Vol. 546; p. 149149
• Main Authors: Jeong, Eunwook, Lee, Taehyeong, Lee, Sang-Geul, Yu, Seung Min, Bae, Jong-Seong, Lee, Gun-Hwan, Choi, Dooho, Yun, Jungheum
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30-04-2021
• Subjects: Atomic oxygen; Silver; Thermal dewetting; Transparent heater; Ultrathin film; Ultrathin film; Atomic oxygen; Silver; Thermal dewetting; Transparent heater
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2021.149149

An effective synthetic strategy based on atomic O-mediated Ag growth is presented for suppressing the thermal dewetting of ultrathin Ag films in an oxide/metal/oxide configuration.
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•A design rule of ultrathin Ag films provides structural stability against thermal dewetting.•Atomic O-mediated Ag growth is suggested for suppressing thermal dewetting.•Atomic O segregation at Ag surfaces ensures a reduction in surface free energy.•Surface free energy reduction facilitates the wetting improvement of Ag on oxides.•Better structural perfection and reduced surface free energy suppress atomic Ag migration.
The structural deformation of a continuous thin film to discrete nanoscopic particles due to solid-state thermal dewetting has been considered an inevitable consequence of using ultrathin Ag films under severe thermal and electrical loading conditions. Thermal dewetting diminishes the electrical and optical performance of Ag film electrodes. Herein, a highly smooth, less defective, completely continuous ultrathin Ag film was used to prove the effectiveness of the atomic O-mediated Ag growth mode in suppressing thermal dewetting. The strong O interference at the outermost surfaces of the Ag nanoscopic geometries provided morphological perfection and chemical modification that contributed to the suppression of the migration of thermally activated Ag atoms. The alleviation of thermal dewetting could be attributed to the reduction in free energies because of the incorporation of the minimal amount of oxygen atoms into interstitial Ag lattice sites without forming oxide phases. The ultrathin (4.5 nm) Ag films sandwiched between thin ZnO films maintained a strong structural integrity and high electrical endurance by successfully circumventing thermal dewetting after exposure to high annealing temperatures up to 673 K and under heavy voltage loading conditions. This facilitated the integration of the heat generating and saving functions, while maintaining optical transparency.