Nickel nanowire synthesis for next-generation transparent conductors

• Autor(a) principal: Domingos, Ismael Duarte
• Data de Publicação: 2016
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/21757
• topic: Nickel nanowires; Hydrothermal synthesis; Electrodeposition; Anodized alumina membrane; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia dos Materiais

Nowadays, transparent and touch-related interaction are two significant trends in information and communication technologies (ICTs). For this reason new alternatives to indium-tin oxide (ITO) are being developed, with this work focusing on one possible approach, based on nickel nanowire networks. These are interesting because of its characteristic high conductivity derived from the metal properties, while having the advantage of the chosen material existing with a large abundance, with much lower cost than materials like indium or silver. Several methods for producing these structures were studied. Initially by an hydrothermal process that proved necessary to have a good control of the applied magnetic field, allowing to obtain nanowires with diameters of 800nm but with a wide variety of lengths. To assure a better process control another route was explored, based on electrodeposition using a mold, varying the reaction time, the applied current and also the electrolyte concentration. For this mold was firstly used an anodized alumina membrane that revealed to require a good etching process of the contact in the mold for a good separation to occur between this and the final product. This resulted in nanowires with about 200 nm diameter and lengths around 60 μm. Finally, alternative materials were used for molds, such as wax, polydimethilsiloxane (PDMS) and epoxi-based photoresist (SU-8), but all resulted in low aspect ratio structures. This work opens pathways for low cost conductive nanostructures, with applications ranging from transparent conductors to 3D interconnectivity in integrated circuits.