Financial source: Miniesterio de Ciencia e Innovación
Principal Investigator: Alberto Palmero
Research team: Rafael Álvarez Molina, Víctor J. Rico Gavira, Agustín R. González-Elipe
This project aims at studying atomic nucleation and thin film growth phenomena on piezoelectric surfaces under acoustic excitation in vacuum/plasma environments. Piezoelectric materials are characterized by a non-zero polarization vector when subjected to mechanical deformation and the reverse, a mechanical deformation when subjected to an electrical excitation. While piezoelectric surfaces under acoustic excitation are being used for numerous applications, e.g. raindrop sensors, touch-sensitive screens, or handling of liquids at the microscale, among others, a systematic survey of the literature reveals that only a seminal work published by the research team addresses the effect of acoustic waves in nucleation and growth processes in a plasma environment. There, we demonstrated a strong correlation between the features of the acoustic wave, the associated polarization pattern on the piezoelectric material and the structural features of a surface grown in the presence of a plasma, suggesting that this interaction can be employed as a new methodology to tailor the film nanostructure.
Two main sources of interaction are analyzed in this project: i) the mechanical influence of the propagating acoustic wave on the surface-induced mobility processes of ad-atoms, ii) the interaction between the polarization wave on the piezoelectric and the plasma electric field lines, that may affect the transport of charged species and their impingement on the piezoelectric material during growth. In this way, this project focusses on the description, development and understanding of a new phenomenology, and on the provision of the fundamental and theoretical framework to describe this interaction. It is expected that acoustic waves activation and its effect on surrounding plasmas represents a radically new procedure to activate thin film growth and nuclei formation and that the proposed methodology goes beyond any present paradigm in the field of surface physics, envisaging new routes of nanostructuration. Similarly, in the field of plasma dynamics, the possibility of modulating the plasma/surface interaction by acoustic waves is an option that may open alternative procedures for the operation of advanced microplasmas devices or flat plasma displays.