Dynamics and Kinetics of Pulsed Laser Deposition: Time-Resolved Synchrotron X-ray Studies

Cornell University, Ithaca NY

Investigators

Abstract

Non-Technical Abstract This project will use time-resolved, x-ray techniques to characterize the atomic scale processes governing the growth of thin-films via pulsed laser deposition (PLD). Due to the atomic nature of materials, attaining the ultimate in device performance is expected to require atomic-level precision in the preparation of surfaces and interfaces. The properties of oxide films are very sensitive to oxygen content. For example, a small increase in oxygen concentration changes strontium titanate films from an insulator into a semiconductor and then into a metal. Developing the ability to control and confine oxygen vacancies remains an important barrier to realizing the full potential of oxide electronic devices. This project will develop and explore the potential of a new technique (time-resolved diffuse x-ray scattering) to characterize oxygen vacancies in such films during their preparation. This project will support intensive training in advanced synchrotron-based x-ray techniques and in the growth of complex oxide thin-films by PLD to a graduate student and a post-doctoral research associate. The PI will continue to work with elementary and middle school teachers on projects developing hands-on modules tailored to meet the goals of the NY state mandated physics curriculum and to disseminate these materials at in-service teacher training events. Technical Abstract This project will use time-resolved, synchrotron-based, hard x-ray (10 KeV) techniques to characterize the atomic scale processes governing the growth of thin-films via pulsed laser deposition (PLD). This project will explore the potential of using the diffuse x-ray scattering from the long-range strain fields of point defects (Huang scattering) to characterize the concentration, spatial distribution, symmetry, and anticipated clustering of oxygen vacancies in SrTiO3 films deposited via PLD. In contrast to spectroscopic techniques which are sensitive to the concentration of atoms or molecules, diffuse x-ray scattering is directly sensitive to the vacancy concentration. This project will support intensive training in advanced synchrotron-based x-ray techniques and in the growth of complex oxide thin-films by PLD to a graduate student and a post-doctoral research associate. The PI will continue to work with elementary and middle school teachers on projects developing hands-on modules tailored to meet the goals of the NY state mandated physics curriculum and to disseminate these materials at in-service teacher training events.