Silver Nanoparticle Arrays onto Glass Substrates Obtained by Solid-State Thermal Dewetting: A Morphological, Structural and Surface Chemical Study

Silver nanoparticles (NPs) on glass substrates were obtained by a solid-state thermal dewetting (SSD) process using vacuum-evaporated-silver precursor layers. An exhaustive investigation of the morphological, structural, and surface chemistry properties by systematically controlling the precursor film thickness, annealing temperature, and time was conducted. Thin silver films with thicknesses of 40 and 80 nm were deposited and annealed in air by applying a combined heat-up+constant temperature–time program. Temperatures from 300 to 500 °C and times from 0 to 50 min were assayed. SSD promoted the morphological modification of the films, leading to the Ag NPs having a discrete structure. The size, shape, surface density, and inter-nanoparticle distance of the nanoparticles depended on the initial film thickness, annealing temperature, and time, exhibiting a cubic silver structure with a (111) preferred crystallographic orientation. The prepared NPs were found to be highly enriched in the Ag{111}/Ag{110}/Ag{100} equilibrium facets. SSD not only promotes NP formation but also promotes the partial oxidation from Ag to AgO at the surface level. AgO was detected on the surface around the nanoparticles synthesized at 500 °C. Overall, a broad framework has been established that connects process factors to distinguish resultant Ag NP features in order to develop unique silver nanoparticles for specific applications.Partial funding for open access charge: Universidad de Málaga. This research was funded by CSIC (Comisión Sectorial de Investigación Científica) of the Universidad de la República, in Montevideo, Uruguay, PEDECIBA—Física, Uruguay. DI Consolidado 039.361/2019 PUCV Project, Valparaíso, Chile. Junta de Andalucía of Spain through the projects UMA18-FEDERJA-041 and UMA18-FEDERJA-039. The APC was funded by PEDECIBA—Física, Uruguay. DI Consolidado 039.361/2019 PUCV Project, Valparaíso, Chile. Junta de Andalucía of Spain through the projects UMA18-FEDERJA-041 and UMA18-FEDERJA-039

Characterization of ZnO and ZnO:Al thin films deposited by the sol-gel dip-coating technique

Nanocrystalline zinc oxide films have been obtained by the sol-gel process. The films were deposited from precursor solutions by dip-coating on quartz substrates, and subsequently transformed into nanocrystalline pure or aluminium-doped ZnO films after a thermal treatment. The film microstructure and composition characterization was studied by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The optical properties were studied by transmittance spectroscopy. The water adsorption energy was measured by temperature programmed desorption (TPD) in the range 90-700 K. The optical transmittance in the UV region gives bandgap energy values of 3.27 eV for undoped samples, and higher than 3.30 eV for the Al-doped ones. The increase in bandgap energy in Al-doped samples may be explained by band-filling effects. The band edge absorption coefficient increases monotonically for the Al-doped samples but has a shoulder for the undoped ones, which may be assigned to room-temperature excitonic absorption.Fil: Marotti, R. E.. Universidad de la República; UruguayFil: Bojorge, Claudia Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación en Láseres y Aplicaciones; Argentina. Repsol-YPF; ArgentinaFil: Broitman, E.. Carnegie Mellon University; Estados UnidosFil: Canepa, Horacio Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas de las Fuerzas Armadas. Centro de Investigaciones en Sólidos; Argentina. Instituto de Investigaciones Científicas y Técnicas de las Fuerzas Armadas; ArgentinaFil: Badán, J. A.. Universidad de la República; UruguayFil: Dalchiele, E. A.. Universidad de la República; UruguayFil: Gellman, A. J.. Carnegie Mellon University; Estados Unido