Silicon nitride membranes were nanopatterned and then folded into three-dimensional (3D) configurations. The out-of-plane folding was achieved using stressed metal hinges. The concept of folding nanopatterned membranes into 3D shapes is referred to as nanostructured origami because of the similarity to the Japanese paper-art of origami, in which two-dimensional surfaces are folded into volumetric shapes. The stressed metal hinges were modeled analytically and compared to experiment. Experimental results demonstrated controllable folding of nanopatterned silicon nitride membranes.

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Multiwalled carbon nanotubes (CNTs) with nickel and cobalt catalyst tips have been grown on foldable titanium nitride membranes. Once magnetized to saturation under an external magnetic field, these ferromagnetic tips, which reside atop each CNT, can be used to actuate the entire membrane on which the nanotubes are grown. Magnetic modeling is performed to analyze the magnetic properties of the teardrop-shaped CNT tips, and initial experimental results show that magnetic torques and forces arising from the CNT tips are sufficient to rotate the membrane up to 180° and keep it latched without springing back.

We demonstrate self-alignment and tunable displacements of released nanopatterned membranes by use of arrays of nanomagnets. The nanomagnet arrays attract and align when brought into close proximity resulting in sub-200nm accurate self-alignment between membrane segments of >50μm lateral size. The alignment is made reconfigurable by patterning the nanomagnets so that there are multiple stable alignment states. An external field is used to transfer between alignment states by applying a magnetic torque on the arrays and by shifting the nanomagnet polarity. Realignment via folding and unfolding of membranes was demonstrated using 75nm thick cobalt nanomagnets patterned on 1um thick silicon nitride membranes. Accurately aligned reconfigurable 2D or 3D nanophotonic systems, such as active photonic crystals and sheared photonic crystal waveguides, may be fabricated with this method.