Estudo sistemático do processo de adsorção induzida por laser de vapor de césio em superfície dielétrica

• Ano de defesa: 2013
• Autor(a) principal: Martins, Weliton Soares
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal da Paraí­ba; BR; Física; Programa de Pós-Graduação em Física; UFPB
• Palavras-chave em Português: Adsorcao; Interação átomo-superficie; Crescimento de filmes; Litografia; Adsorption; Interaction atom-surface; Films growth; Lithography; CIENCIAS EXATAS E DA TERRA::FISICA
• Link de acesso: https://repositorio.ufpb.br/jspui/handle/tede/5759

The ability to manipulate the adsorption process is very desirable. The possibility of understanding and eventually modifying the underlying mechanism is an intriguing task in fundamental physics as well as useful for applications. Indeed, the ability to control the adsorption processes is motivated by the control of thin film growth, by exploring ways to transfer patterns to a surfaces in development of microelectronics, as well as by constructing nanometer-scaled structures which are very important in the development of quantum devices. A first theoretical proposal (De Silans et al. 2006) has been done on controlling the adsorption of cold alkali atoms in dielectric surfaces using laser light. In 2007, Balykin and co-workers (Afanasiev et al. 2007) demonstrated laser-induced adsorption of hot atoms on a surface. They reported that sending a powerful near resonant laser to the interface between a dielectric surface and an alkali vapour leads to the formation of a metallic thin film, and demonstrated the possibility of using such a technique for sub-micrometer lithography. The aim of this work is to systematically study the process of laser induced hot atomic cesium vapor adsorption so as to understand the underlying mechanism as well as to control the process. We monitor the rate of a thin film growth during an induced adsorption process onto a characterized crystalline surface (sapphire) for a prescribed set of experimental conditions in order to be able to decipher, at the atomic level, the rules governing the evolution of the growth (physisorption or chemisorption), and to explore ways to tailor the film shape (lithography). To probe the film growth, we detect the transmission of a He:Ne laser, thus monitoring the time evolutionof the film's thickness. In this way we obtain the growth rate as a function of experimental parameters (vapour density, laser frequency and power and surface temperature). The data obtained we used to model the physical processes involved in the light-induced adsorption.