SnO₂ Nanowire Logic Devices on Deformable Nonplanar Substrates

Logic inverters consisting of n-type FETs and resistors with SnO(2) nanowire channels were fabricated on films of the elastomer polydimethylsiloxane, prestrained and flattened into planar sheets from initial, preformed hemispherical shapes. Upon release, thin and narrow interconnects between individual devices in the arrays absorb induced strain by buckling into nonplanar sinusoidal shapes, to allow full recovery of the surfaces to their original convex geometries. The same physics allows deformation of convex shapes into concave ones, as well as more complex surfaces of coexisting convex and concave areas, and small regions with extremely stretched, locally tapered forms, all nondestructively achieved while maintaining electrical performance, enhanced by use of air gap gate dielectrics. This work shows, more generally, that nanowire devices with both conventional and unusual designs can be integrated into overall systems with irregular, nonplanar layouts, easily deformed in reversible fashion without any measurable alteration in electrical characteristics. The results suggest potential applicability of nanowire technologies in systems of tissue-matched implantable electronics for mounting directly on human organs or of sensor skins for integration with robotic manipulators.