Ultra-thin freestanding ceria membranes: layer transfer techniques and high temperature conductivity studies

Abstract

Interrogation of conduction mechanisms in quasi two-dimensional (2D) brittle or highly resistive materials that are in a suspended form presents a formidable experimental challenge. We report high temperature conductivity studies on substrate-free self-supported nano-crystalline ceria membranes up to 800 K utilizing a layer transfer method that enables four-terminal carrier transport studies under extreme environments. Utilizing such structures we observe increasing conductivity with oxygen partial pressure directly opposing the behavior of thin film devices ‘clamped’ by the substrate. We illustrate that the relaxed nature of free standing membranes, and increased surface to volume ratio enable a more sensitive electrical response to oxygen adsorption on the surface which could have implications for their use in oxygen storage devices, solid oxide fuel cells, and chemical sensors.