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Well-crystallized ZnO nanowires have been successfully synthesized on NiCl2-coated Si substrates via a carbon thermal reduction deposition process. The pre-deposited Ni nanoparticles by dipping the substrates into NiCl2 solution can promote the formation of ZnO nuclei. The as-synthesized nanowires were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) spectrum. The results demonstrate that the as-fabricated nanowires with about 60 nm in diameter and several tens of micrometers in length are preferentially arranged along [0001] direction with (0002) as the dominate surface. Room temperature PL spectrum illustrates that the ZnO nanowires exist a UV emission peak and a green emission peak, and the peak centers locate at 387 and 510 nm. Finally, the growth mechanism of the nanowires is briefly discussed.

Two types of novel bicrystalline ZnO nanowires have been synthesized by a thermal evaporation method. The morphology and microstructure of the nanowires have been extensively investigated. One type of the nanowires has agg twin boundary extending down its entire length with twinning plane and the zone axis. The other type is those nanowires with twin crystal-single crystal junction. The twin defects in the Sn-Zn alloy droplets in the initial growth process are proposed for interpreting the growth of these two kinds of bicrystalline nanowires.

GaN nanowires doped with Mg have been synthesized at different temperature through ammoniating the magnetron-sputtered Ga2O3/Au layered films deposited on Si substrates. X-ray diffraction (XRD), Scanning electron microscope (SEM), high-resolution TEM (HRTEM) equipped with an energy-dispersive X-ray (EDX) spectrometer and photoluminescence (PL) were used to analyze the structure, morphology, composition and optical properties of the as-synthesized sample. The results show that the ammoniating temperature has a great impact on the properties of GaN. The optimally ammoniating temperature of Ga2O3/Au layer is 900 ∘C for the growth of GaN nanowires(NWs). The band gap emission (358 nm) relative to that (370 nm) of undoped GaN NWs has an apparent blueshift, which can be ascribed to the doping of Mg. Finally, the growth mechanism is also briefly discussed.

In this work, GaN nanowires were fabricated on Si substrates coated with NiCl2 thin films using chemical vapor deposition (CVD) method by evaporating Ga2O3 powder at 1100 °C in ammonia gas flow. X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscope (HRTEM) and photoluminescence (PL) spectrum are used to characterize the samples. The results demonstrate that the nanowires are single-crystal GaN with hexagonal wurtzite structure. The growth mechanism of GaN nanowires is also discussed.

GaN nanowires doped with Mg have been synthesized on Si (111) substrate through ammoniating Ga 2 O 3 films doped with Mg under flowing ammonia atmosphere. The Mg-doped GaN nanowires were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), high-resolution transmission electron microscopy (HRTEM) and photoluminescence (PL). The results demonstrate that the nanowires were single crystalline with hexagonal wurzite structure. The diameters of the nanowires ranged 20–30 nm and the lengths were about hundreds of micrometers. The intense PL peak at 359 nm showed a blueshift from the bulk band gap emission, attributed to Burstein–Moss effect. The growth mechanism of the crystalline GaN nanowires is discussed briefly.

Magnesium-doped GaN nanowires with different dopant concentrations are synthesized and their morphology, structure, growth properties, crystallinity, and optical properties investigated. The nanowires are single-crystalline with hexagonal wurzite structure, and doping with 5 atom % of Mg gives nanowires with the best morphology and crystallinity (see HRTEM image). Magnesium-doped GaN nanowires with different dopant concentrations are synthesized by ammoniating Ga2O3 thin films doped with Mg at 900 °C. Scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), high-resolution transmission electron microscopy (HRTEM), and room-temperature photoluminescence (PL) are employed to characterize the influences on the morphology, structure, crystallinity, and optical properties of Mg-doped GaN nanowires. The results demonstrate that the nanowires are single-crystalline with hexagonal wurzite structure. GaN nanowires doped with 5 atom % of Mg have the best morphology and crystallinity with a single-crystalline structure, and at this composition the PL spectrum with the strongest UV peak is observed. The growth mechanism of crystalline GaN nanowires is discussed briefly.

ZnO films are firstly prepared on Si substrates by pulsed laser deposition (PLD) technique and then the Ga 2 O 3 films are deposited on ZnO/Si substrates by magnetron sputtering system. The low-dimensional GaN nanostructured materials are obtained by ammoniating the Ga 2 O 3 /ZnO films from 850 to 1000 °C for 15 min in a quartz tube. X-ray diffraction (XRD), scanning electron microscope (SEM), field-emission transmission electron microscope (FETEM), Fourier transform infrared spectrophotometer (FTIR) and photoluminescence (PL) are used to analyze the structure, morphology and optical properties of as-grown samples. The results show that their properties are investigated particularly as a function of ammoniating temperatures. Large quantities of high-quality GaN nanowires are successfully fabricated at 900 °C with lengths of about tens of micrometers and diameters ranging from 30 to 120 nm, which could supply an attractive potential to harmonically incorporate future GaN optoelectronic devices into Si-based large-scale integrated circuits. Finally, the growth mechanism is also briefly discussed.

GaN nanowires have been successfully synthesized on Si(111) substrate by ammoniating Ga"2O"3 films at 950^oC. The structure and morphology of GaN nanowires are characterized by X-ray diffraction, scanning electron microscopy, field-emission transmission electron microscope and X-ray photoelectron spectroscopy. The results show that the synthesized nanowires are single-crystal hexagonal wurtzite GaN with diameters ranging from 50 to 100nm and lengths up to several microns. Finally, the growth mechanism of GaN nanowires is explored.

Single-crystalline wurtzite GaN nanowires have been synthesized through ammoniating Ga2O3/Ta films by RF magnetron sputtering. The products have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), X-ray photoelectron microscopy (XPS) and photoluminescence (PL). The results show that the nanowires have a hexagonal wurtzite structure with diameters ranging from 10 nm to 30 nm and lengths typically up to several tens of micrometers. The representative photoluminescence spectrum at room temperature exhibits a strong UV light emission band centered at 364 nm. The growth mechanism of the crystalline GaN nanowires is discussed briefly.

Rare earth metal seed Tb was employed as catalyst for the growth of GaN wires. GaN nanowires were synthesized successfully through ammoniating Ga 2 O 3 /Tb films sputtered on Si(1 1 1) substrates. The samples characterization by X-ray diffraction and Fourier transform infrared indicated that the nanowires are constituted of hexagonal wurtzite GaN. Scanning electron microscopy, transmission electron microscopy, and high-resolution transmission electron microscopy showed that the samples are single-crystal GaN nanowire structures. The growth mechanism of the GaN nanowires is discussed.

GaN nanowires and nanorods have been successfully synthesized on Si(1 1 1) substrates by magnetron sputtering through ammoniating Ga 2 O 3 /V films at 900 °C in a quartz tube. X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectrum were carried out to characterize the structure, morphology, and photoluminescence properties of GaN sample. The results show that the GaN nanowires and nanorods with pure hexagonal wurtzite structure have good emission properties. The growth direction of nanostructures is perpendicular to the fringes of (1 0 1) plane. The growth mechanism is also briefly discussed.

Single-crystalline GaN nanowires and nanorods have been successfully grown on Si(1 1 1) substrates by magnetron sputtering through ammoniating the Ga 2 O 3 /Nb films at 900 °C in a quartz tube. The GaN nanowires and nanorods have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), field-emission transmission electron microscope (FETEM), and photoluminescence. The results show that the diameters of the nanowires are about 50 nm while the diameters of the nanorods are within 100–200 nm. Photoluminescence of the GaN nanostructure materials revealed only a strong and broad UV light emission peak at 369 nm. Finally, the growth mechanism of GaN nanostructure materials is also briefly discussed.

Needle-shaped GaN nanowires have been synthesized on Si (111) substrate through ammoniating Ga2O3/MgO films under flowing ammonia atmosphere at the temperature of 950 °C. The as-synthesized GaN nanowires were characterized by X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy, scanning electron microscope (SEM) and high-resolution transmission electron microscopy (HRTEM). The results demonstrate that these nanowires are hexagonal GaN and possess a smooth surface with an average diameter about 200 nm and a length ranging from 5 μm to 15 μm. In addition, the diameters of these nanowires diminish gradually. The growth mechanism of crystalline GaN nanowires is discussed briefly.

GaN nanowires were successfully synthesized on Si(111) substrates by ammoniating the Ga 2 O 3 /ZnO films at 900 °C. The structure, morphology and optical property of the as-prepared GaN nanowires were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), field-emission transmission electron microscope (FETEM), Fourier transform infrared spectrum (FTIR) and fluorescence spectrophotometer. The results show that the GaN nanowires have a hexagonal wurtzite structure with lengths of about several micrometers and diameters ranging from 30 nm to 120 nm. The representative photoluminescence spectrum at room temperature exhibited a strong emission peak at 374.1 nm and two weak emission peaks at 437.4 nm and 473.3 nm. Finally, the growth mechanism is also briefly discussed.

GaN nanowires were synthesized by ammoniating Ga2O3 films on Ti layers deposited on Si (111) substrates at 950 °C. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transformed infrared spectroscopy (FTIR) and high-resolution transmission electron microscopy (HRTEM). The XRD, FTIR and HRTEM studies showed that these nanowires were hexagonal GaN single crystals. SEM observation demonstrated that these GaN nanorods with diameters ranging from 50 nm to 100 nm and lengths up to several micrometers intervene with each other on the substrate.

Actinomorphic GaN nanowires clusters have been achieved by ammoniating Ga2O3 thin films deposited on the Mg layer on the Si (1 1 1) substrate. The resulting materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and selected-area electron diffraction (SAED). SEM images show that the resulting materials are actinomorphic nanowires clusters with the glazed surface. XRD, HRTEM and SAED indicate that the nanowires are single-crystal hexagonal GaN with a wurtzite structure.

This paper reports that Zn 3 N 2 nanowires of high quality can be synthesized by the nitridation reaction of Zn powders with a flowing NH 3 gas in 500 ml/min at the nitridation temperature of 600 °C for 120 min. Surveys by using X-ray diffraction (XRD) indicate that Zn 3 N 2 nanowires has a cubic structure with lattice constants a = 9.788 A. Observations by using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) show that Zn 3 N 2 is of nanowire structure.

A new method was employed to obtain GaN nanowires (NWs). In this method, SiC films were deposited with radio frequency (r.f.) magnetron sputtering onto silicon substrates and annealed at high temperature, and then Ga 2 O 3 films were deposited on top of the SiC intermediate layers and annealed in NH 3 atmosphere. SiC layer was used to reduce thermal and lattice mismatch between GaN and Si, and improve NWs’ quality. After Ga 2 O 3 films reacted with NH 3 , a great quantity of GaN NWs with the shape of birch trunks and stalactites were found by transmission electron microscopy (TEM). At the same time, a few very even and uniform pillarlike NWs were observed. The electron diffraction patterns (EDP) show that birch trunk-shaped and pillarlike NWs are all single-crystalline structures. These NWs were also analyzed with the assistance of X-ray diffraction (XRD), Fourier transformed infrared spectra (FTIR) and high-resolution transmission electron microscopy (HRTEM) to show their properties.

Synthesizing hexagonal wurtzite GaN nanowires involves nitriding Ga2O3 films, which deposited on GaAs(1 1 0) substrates with electrophoresis. The cylindrical structures of GaN nanowires with the diameters ranging from 40 to 200 nm and lengths up to over 100 μm have been obtained. Scanning electron microscopy (SEM) images showed the morphologies of the one-dimensional single crystal materials containing straight and curved nanowires. GaN spherical crystals attached to the fibers with diameters about 600 nm were detected for the first time. The synthesis of one-dimensional GaN nanowires can be achieved without assistance of a template of a catalyst.

Nanostructure GaN films were prepared by post-nitridation technique. The morphology and structure of GaN nanowires are investigated by using transmission electron microscopy and scanning electron microscopy. The growth mechanism of the GaN nanowires is unlikely to be controlled by the well-known vapor–liquid–solid mechanism, vapor–solid phase was involved in the growth of GaN nanostructures. A strong blue photoluminescence is observed for room temperature measurement.

GaN nanowires were synthesized successfully through ammoniating Ga 2 O 3 /NiCl 2 films deposited on the unpolished Si substrate. X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscope (HRTEM) and Fourier transformed infrared spectra (FTIR) are used to characterize the samples. The results demonstrate that the nanowires are single-crystal GaN with hexagonal wurtzite structure. The growth mechanism of GaN nanowires is also discussed.

Large-scale GaN nanowires were synthesized on Si(111) substrates through ammoniating Ga2O3/V films. The as-grown products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results reveal that the grown GaN nanowires have a smooth and clean surface with diameters ranging from 20 nm to 60 nm and lengths of about several tens of micrometers. The results of HRTEM and selected-area electron diffraction (SAED) show that the nanowires are pure hexagonal GaN single crystal. The photoluminescence (PL) spectrum indicates that the GaN nanowires have good emission property. The growth mechanism is discussed briefly.

We have synthesized novel diode-shape ZnO nanocrystals via a simple solid–vapor approach. This new nanostructure is constructed by two basic parts: a hexagonal nanorod and ultra-long nanowires on the two tips of the nanorod. The whole structure is a perfect single crystal along the [0001] growth direction with the length of a few 10 mm. This configuration is a new member in the family of ZnO nanostructures. Based on our XRD and electron microscopy study, the new effect of Sn in the growing process is discussed.

GaN nanowires are successfully synthesized on Si(111) substrates through ammoniating the Ga2O3/ZnO films by radio frequency magnetron sputtering system. X-ray diffraction (XRD), scanning electron microscope (SEM), field-emission transmission electron microscope (FETEM), and Fourier transform infrared spectroscopy (FTIR) are employed to examine the structural and surface morphological properties of the as-prepared GaN nanowires. The results show that the single-crystal GaN nanowires have a hexagonal wurtzite structure with lengths of about several micrometers and diameters ranging from 60 to 160 nm, which is conducive to the application of nanodevices. The assistance of the volatilization of ZnO buffer layer has a great impact on the growth of GaN nanowires. The growth mechanism is also briefly discussed.

The GaN nanowires were successfully synthesized on Si(111) substrates by ammoniating the Ga2O3/ZnO films at 900 °C. The structure and morphology of the as-prepared GaN nanowires were studied by X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), scanning electron microscopy (SEM) and field-emission transmission electron microscopy (FETEM). The results show that the single-crystal GaN nanowires have a hexagonal wurtzite structure with lengths of about several micrometers and diameters ranging from 30 nm to 120 nm, which are conducive to the application of nanodevices. Finally, the growth mechanism is also briefly discussed.

GaN nanowires have been synthesized on Si(111) substrate through ammoniating Ga 2 O 3 /BN films under flowing ammonia atmosphere at the temperature of 900 °C. The as-synthesized GaN nanowires were characterized by X-ray diffraction (XRD), selected-area electron diffraction (SAED), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscope (SEM) and transmission electron microscope (TEM). The results demonstrated that the nanowires are hexagonal wurtzite GaN and possess a smooth surface with diameters ranging from 40 to 100 nm and lengths up to several tens of micrometers. The growth mechanism of crystalline GaN nanowires is discussed briefly.

GaN nanowires were successfully synthesized at high quality and large yield on Si (1 1 1) substrate through ammoniating Ga 2 O 3 /BN films deposited by radio frequency (RF) magnetron sputtering system. X-ray diffraction (XRD), Fourier transformed infrared spectra (FTIR) and selected-area electron diffraction (SAED) confirm that the as-synthesized nanowires are of a hexagonal GaN with wurtzite structure. Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) reveal that the nanowires have a straight and smooth curved structure with extremely uniform diameter of about 60 nm, which is helpful to the application of GaN nanowires. The present results demonstrate that the BN is a very important intermedium in the growth of GaN nanowires by this method.

Liquid-medicine-filter shaped ZnO nanostructures have been synthesized on Al2O3-coated Si (1 1 1) substrates by chemical vapor deposition method (CVD) at 1050 °C. Every liquid-medicine-filter shaped ZnO nanostructure is made up of one nanorod and two nanowires at the ends. The liquid-medicine-filter shaped ZnO nanostructures are characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), energy dispersive spectrometer (EDS) photoluminescence (PL). The results indicate that the liquid-medicine-filter shaped ZnO nanostructures are wurtzite hexagonal structure and the growth direction is [0 0 0 1]. The liquid-medicine-filter shaped ZnO nanostructures became the new member of ZnO nanostructures for the novel configuration. PL reveals ultraviolet (UV) emission at 384 nm and a broad emission peak at 540 nm. These novel liquid-medicine-filter shaped ZnO nanostructures will provide an improvement for electronic and optical devices. The pre-prepared Al2O3 film on the Si (1 1 1) substrate solves the troublesome lattice mismatch problem between the Si substrate and ZnO, and makes the growth of liquid-medicine-filter shaped ZnO nanostructures more effective. In addition, the effect of screw dislocation and polar surfaces in understanding crystal growth mechanisms in nanometer scale were also provided.

A new method using defect-pit-assisted growth technology to successfully synthesize the high-quality single crystalline GaN nanostructures by ammoniating Ga(2)O(3) films was proposed in this paper. During the ammoniating process, the amorphous middle buffer layer may unavoidably produce some defects and dislocations. Some defect pits come out, which have the lowest surface energy and can subsequently be used as a mask/template or act as potential nucleation sites to fabricate the GaN actinomorphic nanostructures. The as-prepared products are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The results indicate that all the reflections of the samples can be indexed to the hexagonal GaN phase and the clear lattice fringes in HRTEM further confirm the growth of high-quality single-crystal GaN nanostructures. The SEM images show that the nanostructures have been realized under different experimental conditions exhibiting different shapes: nanowires, nanorods, and nanobelts. No particles or other nanostructures are found in the SEM study, demonstrating that the product possesses pure nanostructures. These nanostructures show a very good emission peak at 366 nm, which will have a good advantage for applications in laser devices using one-dimensional structures. Finally, the growth mechanism is also briefly discussed.