Effect of Ti and Au buffer layers on controlling the density and wettability of well-aligned ZnO nanorod arrays grown on different substrates.

ZnO nanorod arrays (NRAs) have potential applications as building blocks for nanoscale electronic, optoelectronic, and sensing applications. The density of ZnO NRAs is controlled by a simple low-cost hydrothermal growth process. It is shown that Ti and Au thin buffer layers can be used to control ZnO NRA density up to an order of magnitude on a wide variety of substrates including bare glass AZO, ZnO seeded AZO, FTO and ITO substrates, respectively. We investigate surface morphological, structural and optical properties of ZnO NRAs by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman, and photoluminescence spectroscopy measurements, respectively. To highlight the importance of NRA density, wettability measurements show large dependence on density and static water contact angles range from as low as ∼23° to as large as ∼142°. These results indicate that the capability to control the density of ZnO NRAs, and thus their wettability, can have additional implications such as in their use in biosensors, field emission, dye-sensitized solar-cells (DSSCs), and photocatalytic activity in addition to potential light trapping effects over wide spectral ranges.

Construction and evaluation of high-quality n-ZnO nanorod/p-diamond heterojunctions.

Vertically-aligned ZnO nanorods (NRs) arrays were synthesized by a low-temperature solution method on boron-doped diamond (BDD) films. The morphology, growth direction, and crystallinity of the ZnO NRs were studied by scanning electron microscopy, X-ray diffraction and cathodoluminescence. Electrical characterization of the ZnO NR/BBD heterostructures revealed characteristic p-n junction properties with an on/off ratio of about 50 at +/- 4 V and a small reverse leakage current approximately 1 microA. Moreover, the junctions showed an ideality factor around 1.0 at a low forward voltage from 0 to 0.3 V and about 2.1 for an increased voltage ranging from 1.2 to 3.0 V, being consistent with that of an ideal diode according to the Sah-Noyce-Shockley theory.

Cardiorespiratory effects of epidurally administered ketamine or lidocaine in dogs undergoing ovariohysterectomy surgery: a comparative study.

BACKGROUND: Analgesic and hemodynamic effects of ketamine in subanesthetic doses during surgical anesthesia and postoperative, are due to the action on the N-methyl-D-aspartate receptors (NMDAR). AIMS: To evaluate the intraoperative cardiorespiratory effects provided by ketamine compared to lidocaine, both administered epidurally, in bitches submitted to ovariohysterectomy. METHODS: Thirty-six dogs of different breeds were used in a randomized, prospective, and blinded clinical trial. Two groups were formed: GKET (ketamine 3 mg/kg, n=18) and GLIDO (lidocaine 4 mg/kg, n=18). Animals were premedicated with acepromazine 0.05 mg/kg intravenous. Anesthesia was induced with propofol 5 mg/kg intravenous. Anesthetic maintenance was performed with isoflurane in 100% oxygen. Every 5 min during surgery, heart rate (HR), respiratory rate (RR), esophageal temperature (°C), oxygen saturation (SPO2), end tidal carbon dioxide (ETCO2) and mean arterial pressure (MAP) were monitored. RESULTS: Cardiorespiratory variables during anesthesia were within normal ranges. Heart rate was significantly higher at 5 (108 ± 12 vs 95 ± 11) and 10 (110 ± 11 vs 97 ± 11) min in GKET compared to GLIDO after the start of surgery (P=0.03 and P=0.01, respectively). Mean arterial pressure was higher in GKET, (100 ± 23, 105 ± 35, and 103 ± 35 mmHg) in comparison with GLIDO (66 ± 7, 74 ± 10, and 67 ± 9 mmHg) at 20, 25 and 30 min (P=0.01, P=0.004, and P=0.002, respectively). Mild hypothermia at 25 (36.5 1.3C) and 30 (36.5 1.4C) min in the GKET was recorded. CONCLUSION: Epidural administration of ketamine provides better hemodynamic stability, compared to the use of epidural lidocaine.

Resonance modulated amplified emission from CdSSe nanoribbons.

We present evidence of amplified emission mediated by surface plasmon polaritons (SPPs) from a CdS0.2Se0.8 nanoribbon (NR) supported on a gold-coated silicon substrate. Room temperature amplified emission is observed from the nanoribbon above excitation irradiances ~ 25 W/cm(2) when it is supported on the gold coated silicon substrate. The nanoribbon is shown to act as a resonator cavity, leading to amplification of discrete wavelengths in the emission spectrum. Evidence for the formation of SPP waves between the gold-coated substrate and the nanoribbon is shown, and the resulting wavenumber increase allows for the matching of theoretical resonance wavelengths with those observed experimentally.

Facile and rapid synthesis of highly porous wirelike TiO2 as anodes for lithium-ion batteries.

Highly porous wirelike TiO(2) nanostructures have been synthesized by a simple two-step process. The morphological and structural characterizations reveal that the TiO(2) wires typically have diameters from 0.4 to 2 µm, and lengths from 2 to 20 µm. The TiO(2) wires are highly porous and comprise of interconnected nanocrystals with diameters of 8 ± 2 nm resulting in a high specific surface area of 252 m(2) g(-1). The effects of experimental parameters on the structure and morphology of the porous wirelike TiO(2) have been investigated and the possible formation processes of these porous nanostructures are discussed. Galvanostatic charge/discharge tests indicate that the porous wirelike TiO(2) samples exhibit stable reversible lithium ion storage capacities of 167.1 ± 0.7, 152.1 ± 0.8, 139.7 ± 0.3, and 116.1 ± 1.1 mA h g(-1) at 0.5, 1, 2, and 5 C rates, respectively. Such improved performance could be ascribed to their unique porous and 1D nanostructures facilitating better electrolyte penetration, higher diffusion rate of electrons and lithium ion, and variation of accommodated volumes during the charge/discharge cycles.

Visible-NIR photodetectors based on CdTe nanoribbons.

Zinc blende-structured CdTe nanoribbons (NRs) were synthesized for the first time via a two-step process. The electronic, transport, and photoconductive properties of the CdTe NRs were studied systematically. It was revealed that the CdTe NRs showed p-type conductivity, and presented significant photoresponses to visible-NIR (400-800 nm) irradiation with high responsivity and gain. The contribution of the factors such as surface states of NRs, channel length, light intensity, and working bias voltage to the photoresponse characteristics of CdTe NR photodetectors were discussed. Moreover, single CdTe NR-based visible-NIR photodetectors were also demonstrated to have high stability and reliability.

p-Type ZnO nanowire arrays.

Well-aligned ZnO nanowire (NW) arrays with durable and reproducible p-type conductivity were synthesized on alpha-sapphire substrates by using N2O as a dopant source via vapor-liquid-solid growth. The nitrogen-doped ZnO NWs are single-crystalline and grown predominantly along the [110] direction, in contrast to the [001] direction of undoped ZnO NWs. Electrical transport measurements reveal that the nondoped ZnO NWs exhibit n-type conductivity, whereas the nitrogen-doped ZnO NWs show compensated highly resistive n-type and finally p-type conductivity upon increasing N2O ratio in the reaction atmosphere. The electrical properties of p-type ZnO NWs are stable and reproducible with a hole concentration of (1-2) x 10(18) cm(-3) and a field-effect mobility of 10-17 cm2 V(-2) s(-1). Surface adsorptions have a significant effect on the transport properties of NWs. Temperature-dependent PL spectra of N-doped ZnO NWs show acceptor-bound-exciton emission, which corroborates the p-type conductivity. The realization of p-type ZnO NWs with durable and controlled transport properties is important for fabrication of nanoscale electronic and optoelectronic devices.

Wavelength-Controlled Lasing in Znx Cd1- x S Single-Crystal Nanoribbons.

Znx Cd1 - x S single-crystal nanoribbons of controlled composition (where 0 ≤ x ≤ 1) can be synthesized by combining laser ablation with thermal evaporation. The nanoribbons exhibit lasing emission that can be continuously tuned within the ranges of 340-390 nm and 485-515 nm. These results suggest that Znx Cd1- x S nanoribbon lasers of pre-selected "tunable" wavelengths between 340 and 515 nm may be achievable by tailoring the value of x.