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Significant new mechanical and electronic phenomena can arise in single-crystal semiconductors when their thickness reaches nanometer dimensions, where the two surfaces of the crystal are physically close enough to each other that what happens at one surface influences what happens at the other. We show experimentally that, in silicon nanomembranes,(More)
GCNBs were prepared by chemical vapor deposition at Tokai Carbon Co. Ltd. The detailed preparation procedure has been reported previously [18]. The structure of GCNBs was studied by X-ray diffraction (XRD) (Rigaku, Rint2500), Raman spectroscopy (Jovin-Yvon, T-64 000), and TEM (Hitachi-9000). For the fabrication of GCNB electrodes, each GCNB sample was mixed(More)
Semiconductor nanomembranes are single-crystal sheets with thickness ranging from 5 to 500nm. They are flexible, bondable, and mechanically ultra-compliant. They present a new platform to combine bottom-up and top-down semiconductor processing to fabricate various three-dimensional (3D) nanomechanical architectures, with an unprecedented level of control.(More)
Pseudomorphic three-dimensional Ge nanocrystals (quantum dots) grown on thin silicon-on-insulator substrates can induce significant bending of the silicon template layer that is local on the nanometer scale. We use molecular dynamics simulations and analytical models to confirm the local bending of the Si template and to show that its magnitude approaches(More)
In many neural culture studies, neurite migration on a flat, open surface does not reflect the three-dimensional (3D) microenvironment in vivo. With that in mind, we fabricated arrays of semiconductor tubes using strained silicon (Si) and germanium (Ge) nanomembranes and employed them as a cell culture substrate for primary cortical neurons. Our experiments(More)
Surface energies of Si(0 0 1), (1 1 0), (1 1 1), and (1 1 3) surfaces with different reconstructions are calculated systematically using first-principles total-energy method. In order to quantitatively compare their relative stability, the surface energies of different surface orientations and their respective theoretical bulk atom energies are determined(More)
Mechanical bending is ubiquitous in heteroepitaxial growth of thin films where the strained growing film applies effectively an " external " stress to bend the substrate. Conventionally, when the deposited film is much thinner than the substrate, the bending increases linearly with increasing film thickness following the classical Stoney formula. Here we(More)
Complex three-dimensional (3D) structures in biology (e.g., cytoskeletal webs, neural circuits, and vasculature networks) form naturally to provide essential functions in even the most basic forms of life. Compelling opportunities exist for analogous 3D architectures in human-made devices, but design options are constrained by existing capabilities in(More)
Because of the large surface-to-volume ratio, the conductivity of semiconductor nanostructures is very sensitive to surface chemical and structural conditions. Two surface modifications, vacuum hydrogenation (VH) and hydrofluoric acid (HF) cleaning, of silicon nanomembranes (SiNMs) that nominally have the same effect, the hydrogen termination of the(More)
We demonstrate, by theoretical analysis and molecular dynamics simulation, a mechanism for fabricating nanotubes by self-bending of nanofilms under intrinsic surface-stress imbalance due to surface reconstruction. A freestanding Si nanofilm may spontaneously bend itself into a nanotube without external stress load, and a bilayer SiGe nanofilm may bend into(More)