We report metalorganic vapor-phase epitaxial growth and structural photoluminescent characteristics of ZnO nanorods. The nanorods were grown on Al2O3(00⋅1) substrates at 400 °C without employing any metal catalysts usually needed in other methods. Electron microscopy revealed that with uniform distributions their diameters, lengths, densities vertically from the substrates. mean diameter is as narrow 25 nm. In addition, x-ray diffraction measurements clearly show epitaxially homogeneous...

Silicon is a promising candidate for electrodes in lithium ion batteries due to its large theoretical energy density. Poor capacity retention, caused by pulverization of Si during cycling, frustrates practical application. We have developed nanostructured form silicon, consisting arrays sealed, tubular geometries that capable accommodating volume changes associated with lithiation battery applications. Such exhibit high initial Coulombic efficiencies (i.e., >85%) and stable...

This paper presents a review of current research activities on ZnO nanorods (or nanowires). We begin this with variety physical and chemical methods that have been used to synthesize There follows discussion techniques for fabricating aligned arrays, heterostructures doping nanorods. At the end paper, we discuss wide range interesting properties such as luminescence, field emission, gas sensing electron transport, associated nanorods, well various intriguing applications. conclude personal...

Electroluminescent (EL) devices (see Figure) have been fabricated using n‐ZnO nanorod arrays grown on p‐GaN epilayers. Simple heteroepitaxial growth yields vertically aligned ZnO nanorods with an abrupt interface GaN. The p–n heterojunction EL device shows a high current density and strong electroluminescence even at reverse‐bias voltage of 3 V.

Catalyst‐free metal–organic chemical vapor deposition (MOCVD) is used to prepare ZnO nanoneedles, grown vertically on Si substrates. Electron microscopy reveals that the nanoneedles are sharp, have uniform diameters, lengths, and densities, high crystallinity. The photoluminescence spectrum displays a strong emission peak at 3.29 eV with very weak deep‐level emission, indicating of optical quality.

Highly efficient photocatalytic ZnO nanoneedle arrays with a large surface/volume ratio were prepared on inexpensive, large-area substrates using metal–organic chemical vapor deposition. The activity of is much enhanced due to their increased ratio. It believed that the "bottom–up" approach may be expanded create many other one-dimensional oxide semiconductor nanostructures (see Figure).

We report on the photoluminescent characteristics of ZnO single crystal nanorods grown by catalyst-free metalorganic vapor phase epitaxy. From photoluminescence (PL) spectra at 10 K, several PL peaks were observed 3.376, 3.364, 3.360, and 3.359 eV. The peak 3.376 eV is attributed to a free exciton while other are ascribed neutral donor bound peaks. observation K indicates that prepared method high optical quality.

High-quality Zn1−xMgxO(0.00⩽x⩽0.49) thin films were epitaxially grown at 500–650 °C on Al2O3(00⋅1) substrates using metalorganic vapor-phase epitaxy. By increasing the Mg content in up to 49 at. %, c-axis constant of decreased from 5.21 5.14 Å and no significant phase separation was observed as determined by x-ray diffraction measurements. Furthermore, near-band-edge emission peak position showed blueshifts 100, 440, 685 meV levels 9, 29, respectively. Photoluminescent properties alloy are...

We report on fabrication and electrical characteristics of high-mobility field-effect transistors (FETs) using ZnO nanorods. For FET fabrications, single-crystal nanorods were prepared catalyst-free metalorganic vapor phase epitaxy. Although typical nanorod FETs exhibited good characteristics, with a transconductance ∼140nS mobility 75cm2∕Vs, the device significantly improved by coating polyimide thin layer surface, exhibiting large turn-ON/OFF ratio 104–105, high 1.9μS, electron above...

The electrical properties of flexible nonvolatile organic bistable devices (OBDs) fabricated with graphene sandwiched between two insulating poly(methyl methacrylate) (PMMA) polymer layers were investigated. Current−voltage (I−V) measurements on the Al/PMMA/graphene/PMMA/indium−tin-oxide/poly(ethylene terephthalate) at 300 K showed a current bistability due to existence graphene, indicative charge storage in graphene. maximum ON/OFF ratio for OBDs was as large 1 × 107, and endurance number...

Problems related to tremendous volume changes associated with cycling and the low electron conductivity ion diffusivity of Si represent major obstacles its use in high-capacity anodes for lithium batteries. We have developed a group IVA based nanotube heterostructure array, consisting inner layer highly conductive Ge outer layer, yield both favorable mechanics kinetics battery applications. This type Si/Ge double-layered array electrode exhibits improved electrochemical performances over...

Multiple quantum well nanorods have been fabricated via heteroepitaxial growth of ZnO and ZnMgO (see Figure also cover). Simple yet accurate thickness control allows the realization nanosized structures in individual that are tunable through effects confinement. This approach should be readily extendible to other semiconductor nanorods.

We report on fabrication and electrical characteristics of ZnO nanorod Schottky diode arrays. High quality nanorods were grown for the diodes using noncatalytic metalorganic vapor phase epitaxy Au was evaporated tips vertically well-aligned nanorods. I–V both bare Au/ZnO heterostructure arrays measured current-sensing atomic force microscopy. Although exhibited nonlinear asymmetric characteristic curves, demonstrated much improved characteristics: reverse-bias breakdown voltage from −3 to −8...

Random laser action with coherent feedback has been observed in ZnO nanorod arrays embedded epilayers. The sample was fabricated by depositing a MgO buffer layer and followed of thin film onto vertically well-aligned grown on sapphire substrate. Under 355 nm optical excitation at room temperature, sharp lasing peaks emit around 390 linewidth less than 0.4 all directions. In addition, the dependence threshold intensity area is shown good agreement random theory. Hence, it demonstrated that...

Logic devices, including OR, AND, NOT, and NOR gates, based on single-crystalline ZnO nanorods are demonstrated (see Figure). In these employed as semiconducting channels. They control metal/oxide semiconductor junction characteristics, to yield either good ohmic or Schottky contacts, ensuring fabrication of high-performance diodes metal-semiconductor field-effect transistors.

We report the nanocluster-catalyzed growth of ultralong and highly uniform single-crystalline silicon nanowires (SiNWs) with millimeter-scale lengths aspect ratios up to approximately 100 000. The average SiNW rate using disilane (Si2H6) at 400 °C was 31 μm/min, while determined for silane (SiH4) reactant under similar conditions 130 times lower. Transmission electron microscopy studies millimeter-long SiNWs diameters 20−80 nm show that grow preferentially along ⟨110⟩ direction independent...

We report ZnO nanorod−graphene hybrid architectures (ZnO−G HAs) composed of regular arrays nanorods formed on few-layer graphene films transferred to transparent and/or flexible substrates. The ZnO−G HAs exhibited a high current flow reaching ∼1.1 mA at an applied bias 1 V and good optical transmittance in the range 70−80%, comparable those layer. In addition, cathodoluminescence images photoluminescence spectra showed distinct light emission involving transitions nanorod array. Moreover,...

We report a type of device that combines vertical arrays one-dimensional (1D) pillar-superlattice (PSL) structures with 2D graphene sheets to yield class light emitting diode (LED) interesting mechanical, optical, and electrical characteristics. In this application, coated very thin metal layers exhibit good mechanical properties an ability mount, in freely suspended configuration, on the PSL as top window electrode. Optical characterization demonstrates exhibits excellent optical...

Ultraviolet (UV) photodetectors were fabricated using the wet spin-coating for ZnO quantum dots (QDs) and transfer method graphene sheet. High-resolution transmission electron microscopy images showed that QDs uniformly distributed between voids of surface circumferences on layers. Current-voltage measurements UV photodetector at 300 K ratio photocurrent to dark current was about 1.1 × 104. The rise decay times approximately 2 1 s, respectively. photoresponse mechanisms are described basis...

We report on photoluminescence (PL) spectra of ZnO films grown by low pressure metalorganic vapor phase epitaxy. For PL measurements, high quality thin were epitaxially Al2O3(0001) substrates. Time-integrated the at 10 K clearly exhibited free A and B excitons 3.376 3.382 eV bound exciton peaks 3.360, 3.364, 3.367 eV. With increasing temperature, intensities drastically decreased a peak was dominant above 40 K. Furthermore, time-resolved measurements carried out room temperature. The decay...

Size dependence of the time-resolved photoluminescence (TRPL) has been investigated for ZnO nanorods fabricated by catalyst-free metalorganic chemical vapor deposition. The have a diameter 35 nm and lengths in range 150 to 1.1 μm. TRPL decay rate decreases monotonically as length increases 600 nm. Decrease radiative exciton-polariton invoked account results.

We describe experimental and theoretical studies of the buckling mechanics in silicon nanowires (SiNWs) on elastomeric substrates. The system involves randomly oriented SiNWs grown using established procedures wafers, then transferred organized into aligned arrays prestrained slabs poly(dimethylsiloxane) (PDMS). Releasing prestrain leads to nonlinear mechanical processes that transform initially linear sinusoidal (i.e., "wavy") shapes. displacements associated with these waves lie plane...

We report a new facile route to synthesize the ZnO nanotubes by thermal annealing of solid nanorods in ambient NH3. The unique characteristic this approach allows achievement ultrathin with well-organized hexagonal nanowalls and sealed layouts. On basis our experimental observations, we developed nanotube formation mechanism illustrating following: (i) energetically active nanorod surfaces could be readily passivated form few-atoms-thick Zn3N2 layer (ii) nanopores generated from seed were...

Si‐Ge composites have recently been explored as an anode material for lithium‐ion batteries due to their stable cycle performance and excellent rate capability. Although previous reports show the benefits of on electrochemical performance, specific mechanism structural effects overlooked. Here, effect heterogeneous nanostructures both mechanics kinetics is systematically studied through theoretical analysis detailed experimental results. Ge‐Si core–shell nanowires are employed this study....