We report a successful development of a floating electrode-based DNA sensor with controllable responses. Here, metallic floating electrodes were fabricated to form Schottky barriers between carbon nanotubes and the floating electrodes. We showed that the sensor response could be enhanced by increasing the number of floating electrodes. We also analyzed the response of the sensors based on the Langmuir isotherm theory.

Carbon nanotube (CNT) network-based sensors have been often considered unsuitable for practical applications due to their unpredictable characteristics. Herein, we report the study of universal parameters which can be used to characterize CNT network-based sensors and make their response predictable. A theoretical model is proposed to explain these parameters, and sensing experiments for mercury (Hg(2+)) and ammonium (NH(4)(+)) ions using CNT network-based sensors were performed to confirm the validity of our model.

We present a method for assembling silicon nanowires (Si-NWs) in virtually general shape patterns using only conventional microfabrication facilities. In this method, silicon nanowires were functionalized with amine groups and dispersed in deionized water. The functionalized Si-NWs exhibited positive surface charges in the suspensions, and they were selectively adsorbed and aligned onto negatively charged surface regions on solid substrates. As a proof of concepts, we demonstrated transistors based on individual Si-NWs and long networks of Si-NWs.

The feasibility of the charge-transfer based polymer resistive memory as a future data storage device was tested using a thermally robust polyimide and PCBM composite film, available by low-cost solution processing. The prototype device with a simple 4F cross-point cell structure demonstrated basic non-volatile memory functions (> 1000 write/erase cycles and 1-week data retention in an ambient without encapsulation). Not only bi-polar but also uni-polar operation scheme with multi-level programming worked for the device. The cells on both the top and the bottom layers of a stacked device with additional heat budget of > 300 degC for 1 hour exhibited no degradation on the performance

We observed the irreversible extinction of ferroelectric polarization in spun coated poly(vinylidene fluoride-co-trifluoroethylene) thin films upon melting and recrystallization. We investigate the alteration of the ferroelectric properties correlated with the preferred polymer crystal orientation with respect to the electrodes using grazing incident scattering, spectroscopy, and electron microscopes. Heat treatment above melting point gave rise to the significant reduction of the ferroelectric performance mainly caused by the modification of molecular orientation of polymer crystals whose c and b axes are perpendicular and parallel to the electrode surface, respectively, leading to almost zero effective electric field.

The GaN, GaP, InP, Si 3 N 4 , SiO 2 /Si, SiC, and ZnO semiconductor nanowires were synthesized by a variety of growth methods, and they were wrapped cylindrically with amorphous aluminum oxide (Al 2 O 3 ) shells. The Al 2 O 3 was deposited on these seven different semiconductor nanowires by atomic layer deposition (ALD) at a substrate temperature of 200°C using trimethylaluminum (TMA) and distilled water (H 2 O). Transmission electron microscopy (TEM) images taken for the nanowires revealed that Al 2 O 3 cylindrical shells surround uniformly all these semiconductor nanowires. Our TEM study illustrates that the ALD of Al 2 O 3 has an excellent capability to coat any semiconductor nanowires conformally; its coating capability is independent of the chemical component, lattice structure, and growth direction of the nanowires. This study suggests that the ALD of Al 2 O 3 on nanowires is one of the promising methods to prepare cylindrical dielectric shells in coaxially gated, nanowire field-effect transistors (FETs).