Free standing yttria-doped zirconia membranes: Geometrical effects on stability

tions to the areas of ionic conduction mechanisms in crystal-line and disordered systems. An area of emerging interest in the solid state ionics community is investigating conduction in the mesoscopic regime. With free standing membranes, one can probe low-dimensional effects such as confinement with-out interference from substrates. Membranes have potential relevance to solid state devices that benefit from reduced ionic resistance, for example sensors and solid oxide fuel cells. Membranes with varying lateral dimensions have been previ-ously reported in literature; however, understanding of stress interactions in suspended oxide structures is in early stages. In this paper, we demonstrate self-supported, i.e. in the absence of any additional mechanical support layers, square and cir-cular membranes of 100 nm thick yttria-doped zirconia (YDZ) having side length and diameters of 0.15–2 mm. The buckled membrane shape is intimately linked to the fabrication pro-cesses arising from dry versus wet etching protocols. Geomet-rical considerations associated with buckling and stability are discussed. Thin film solid oxide fuel cells utilizing circular membranes are fabricated, exhibiting open circuit voltages between 0.8 and 1 V that correlate with membrane size and exhibit a total power output on the order of several mW. These results contribute to advancing experimental techniques to fabricate free standing oxide membranes for fundamental and applied studies pertaining to ionic and electronic conduction