New Method for Patterning Semiconductor Oxides Suited for Nonplanar Surfaces

A new method for device fabrication, published online in the January 29, 2009, issue of Applied Physics Letters, allows for submicron resolution patterning of metals, organics and other solid materials on nonconventional – nonplanar – surfaces. Developed in part by assistant professor of chemical engineering, André Taylor, in collaboration with researchers at the University of Michigan, the novel technique uses a room temperature stamping method to transfer patterned, transparent semiconductor, indium tin oxide (ITO) onto an arbitrarily shaped surface – in this case a hemispherical surface that mimics the size and form of the human eye.

 

Traditional stamping or photolithography methods for high resolution patterning on curved architectures require transfer of material first to a flexible, but flat surface, followed by shaping. While this technique works for some designs, the flexible substrate and/or the layers deposited can be damaged or destroyed when deformed beyond a certain point. This is especially problematic with brittle semiconductor oxides and manipulation that requires stretching or compression of the surface. With this research, the authors successfully demonstrate patterning of ITO by direct transfer – cold welding – from an elastomeric or flexible stamp to both planar and three dimensionally deformed surfaces.

 

This method has potential to further rapid fabrication of large area, low cost electronics with applications extending to organic solar cells, photodetectors, and organic light emitting diodes. Taylor, who leads the Transformative Materials and Devices Laboratory at Yale, will continue this research towards developing unique device architectures for energy conversion/storage and portable electronics.