CAREER: Towards rational design and control of oxygen migration in oxide thin films for nano-ionic technologies

University Of Florida, Gainesville FL

Investigators

Abstract

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). PART 1: NON-TECHNICAL SUMMARY Information storage and data processing has traditionally relied on moving electrons back and forth between different materials. In contrast, several emerging technologies rely on moving oxygen ions in and out of thin materials to change their properties, like electrical resistance or magnetism, by changing the materials chemistry. The expected advantages of this latter approach include greater energy efficiency, longer information storage lifetimes, and the ability to support new computing approaches like quantum computing. However, accurately measuring oxygen diffusion in very thin films remains challenging and creates a bottleneck in our ability to understand how different materials hinder or facilitate oxygen ion movement at small length scales. This CAREER project, supported by the Ceramics program in the Division of Materials Research, addresses this bottleneck by developing a new measurement technique to accurately measure oxygen migration through stacks of different thin films and from that extract information about the barrier to oxygen migration created by each layer and the interfaces between them. This knowledge can then be used to design technologies based on ion motion with the same precision that enables silicon-based electronics today. In addition, the educational outreach component of this program creates low-cost activity kits and free training videos to help K-12 teachers introduce students to materials science concepts and teach them about several key electronic devices. These kits are supported by free online videos that reinforce the activity concepts and connect them to ongoing research. Such experiences help create a pipeline of enthusiastic young scientists with an early knowledge of materials science principles and how they can be used to create greener technologies. PART 2: TECHNICAL SUMMARY Controlling nanoscale oxygen migration in thin film heterostructures is important to harnessing the unique functional properties found in strongly correlated oxide materials for the next generation of information technologies. As a step towards improved ionic migration control in oxide films, this CAREER project, supported by the Ceramics program in the Division of Materials Research, creates new measurement capabilities and knowledge in the field of nanoscale ion diffusion. Specifically, this program develops a new in-situ scattering approach to quantify oxygen concentration profiles and extract quantitative diffusion coefficients and activation energies from different heterostructure geometries. Combining this approach with thin film engineering techniques enables the isolation of individual structure-property relationships between elements of the heterostructure design (e.g., strain, layer thickness, layer stacking) and their effect on oxygen migration in prototypical perovskite structures. By coupling these spatially resolved scattering studies with temperature-dependent impedance spectroscopy, this work provides insight into the active diffusion mechanism(s) operative in various heterostructure designs and temperature regimes. In conjunction with these research efforts is an educational plan that creates and distributes electronic materials activity kits designed to support state learning standards and are themselves supported by a database of lay-audience videos connecting core ideas from each activity to ongoing research. Graduate students engaged with the project gain experience in electronic materials synthesis, state-of-the-art characterization methodologies, and scientific communication to a variety of audiences. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.