MULTIPURPOSE XRD HOLDER FOR THE SIMULTANEOUSLY CHARACTERIZATION OF THE STRUCTURAL AND ELECTRICAL PROPERTIES OF VANADIUM OXIDES

• Autor(a) principal: Farto, Miguel Simão
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/82458
• topic: XRD; vanadium oxide; holder; phase change; metal-to-isolation transition; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia dos Materiais

Several oxides present a severe and reversible resistance changes with the application of an external stimulus such as an electrical field, temperature, optical or magnetic properties. Among them there are two groups, those who recover for the initial stage after the stimulus is finished and those who keeps the final stage, despite the stimulus is over. In the first group, vanadium dioxide (VO2), present a sharp and reversible metal-to-insulator transition, induced by temperature near 68 °C. Since is a low transition temperature and presents a high speed and volatile change. In this project we optimize the crystallization of VO2 thin film produced by e-beam evaporation and produced a versatile X-Ray Diffractometer (XRD) holder, capable to be adapted to several other characterization equipment. This holder has the capability to heat and control the temperature applied on the oxide and at the same time perform the electric characterization of the oxide in situ, during the XRD measurement. This holder will be very helpful in characterization of several material due to its ability to have a uniform heating behavior in many equipments, thus ensuring that the process is the same regardless of the equipment used.