Fabrication and characterization of vertically aligned long ZnO nanorods on transparent substrate.

Vertically aligned long ZnO nanorods (NRs) were grown by metal organic chemical vapor deposition (MOCVD) technique. Prior to the NRs growth Ga-doped ZnO (GZO) film was deposited by DC sputtering technique on glass substrates. The length and width of the NRs were 25 microm and 450-500 nm, respectively. Structural and optical properties of the NRs were investigated after the growth. The NRs were single crystalline in nature with the preferred growth along c-axis. The diffusion of Ga atoms in the bottom of the NRs during the growth is detected. A prominent near band edge emission of NRs was observed from room-temperature photoluminescence study. Electrical characteristics across the NRs-thin film hybrid structure were measured with UV exposure, where the rise and fall of the photocurrent was exponential in nature due to the desorption and adsorption of oxygen in the surface.

Programmable direct-printing nanowire electronic components.

In order for recently developed advanced nanowire (NW) devices(1-5) to be produced on a large scale, high integration of the separately fabricated nanoscale devices into intentionally organized systems is indispensible. We suggest a unique fabrication route for semiconductor NW electronics. This route provides a high yield and a large degree of freedom positioning the device on the substrate. Hence, we can achieve not only a uniform performance of Si NW devices with high fabrication yields, suppressing device-to-device variation, but also programmable integration of the NWs. Here, keeping pace with recent progress of direct-writing circuitry,(6-8) we show the flexibility of our approach through the individual integrating, along with the three predesigned N-shaped sites. On each predesigned site, nine bottom gate p-type Si NW field-effect transistors classified according to their on-current level are programmably integrated.

Biomimetic hierarchical ZnO structure with superhydrophobic and antireflective properties.

A two step method, with a combination of top-down and bottom-up approaches, was developed for the fabrication of ZnO based hierarchical structures with nanorods on microcraters. A layer of well c-axis aligned, transparent, conductive ZnO thin film was deposited by pulsed DC sputtering on a Corning glass substrate. The microcraters were created with anisotropic etching on the as-deposited ZnO thin film. ZnO nanorods were then synthesized onto the etched film by means of metal organic chemical vapor deposition. The resulting hierarchical film exhibits a high water contact angle (>160 degrees) with a low contact angle hysteresis (2 degrees) and low reflection over a wide spectral range. This biomimetic material may find potential applications in many industrial fields, e.g., self-cleaning, solar cells, displays.