Synthesis of GaN nanorods by ammoniating Ga2O3 films on TiO2 (rutile) layer deposited on Si(111) substrates

GaN nanorods have been synthesized by ammoniating Ga₂O₃ films on a TiO₂ middle layer deposited on Si(111) substrates. The products were characterized by X-Ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transformed infrared spectra (FTIR) and high-resolution transmission electron microscopy (HRTEM). The XRD analysis indicates that the crystallization of GaN film fabricated on TiO₂ middle layer is rather excellent. The FTIR, SEM and HRTEM demonstrate that these nanorods are hexagonal GaN and possess a rough morphology with a diameter ranging from 200 nm to 500 nm and a length less than 10 μm, the growth mechanism of crystalline GaN nanorods is discussed briefly.     

Synthesis of GaN nanowires through Ga2O3 films' reaction with ammonia

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.     

Synthesis and optical properties of single-crystalline GaN nanorods

Single-crystalline GaN nanorods were successfully synthesized on Si(1 1 1) substrates through ammoniating Ga₂O₃/Mo films deposited on the Si(1 1 1) substrate by radio frequency magnetron sputtering technique. The as-synthesized nanorods are confirmed as single-crystalline GaN with wurtzite structure by X-ray diffraction (XRD), selected-area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM). Scanning electron microscopy (SEM) displays that the GaN nanorods are straight and smooth with diameters in the range of 100-200 nm and lengths typically up to several micrometers. X-ray photoelectron spectroscopy (XPS) confirms the formation of bonding between Ga and N. The representative photoluminescence spectrum at room temperature exhibits a strong and broad emission band centered at 371.1 nm, attributed to GaN band-edge emission. The growth process of GaN nanorod may be dominated by vapor-solid (VS) mechanism.     

Structure and optical spectrum of GaN nanorods produced on Si(111) substrates

A novel method is applied to prepare nanorods. In this method, nanorods have been successfully synthesized on Si(111) substrates through annealing sputtered Ga₂O₃/Nb films under flowing ammonia at 950 °C in a quartz tube. The as-synthesized nanorods are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectra. The results show that the nanorod is single-crystalline GaN. It has a diameter of about 200 nm and lengths typically up to several micrometers. Photoluminescence spectrum under excitation at 325 nm only exhibits a UV light emission peak is located at about 368.5 nm. Finally, the growth mechanism of nanorods is also briefly discussed.     

Effect of ammoniating temperature on morphologic and optical properties of GaN nanostructured materials

GaN nanostructured materials have been obtained on Si(111) substrates by ammoniating the Ga₂O₃/ZnO films at different temperature in a quartz tube. X-ray diffraction (XRD), Scanning electron microscope (SEM), and photoluminescence (PL) are used to analyze the structure, morphology and optical properties of GaN nanostructured films. The results show that their properties are investigated particularly as a function of ammoniating temperature. The optimally ammoniating temperature of Ga₂O₃ layer is 950 °C for the growth of GaN nanorods. These nanorods are pure hexagonal GaN wurtzite structure with lengths of about several micrometers and diameters of about 200 nm, which is conducive to the application of nanodevices. Finally, the growth mechanism is also briefly discussed.     

Catalytic synthesis of large-scale GaN nanorods

A novel rare earth metal seed was employed as the catalyst for the growth of GaN nanorods. Large-scale GaN nanorods were synthesized successfully through ammoniating Ga₂O₃/Tb films sputtered on Si(1 1 1) substrates. Scanning electron microscopy, X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy were used to characterize the structure, morphology, and composition of the samples. The results demonstrate that the nanorods are high-quality single-crystal GaN with hexagonal wurtzite structure. The growth mechanism of GaN nanorods is also discussed.     

The effect of HNO3 on morphology,phase transformation,and luminescence properties of LaPO4:Eu3+ phosphors

LaPO₄:Eu³⁺ powders with different morphologies were hydrothermally constructed by adjusting the amount of HNO₃ without using a catalyst, surfactant, or template. The as-prepared products were characterized by photoluminescence spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution-transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED), X-ray diffraction (XRD), infrared (IR) spectra, and X-ray photoelectron spectroscopy. The SEM study revealed that the amount of HNO₃ played a crucial role in the morphology of the final products. The XRD results indicated that the as-prepared samples were in the monoclinic phase when 3 mL of HNO₃ was used. The HR-TEM micrographs and SAED results demonstrated that the prepared nanorods were single and crystalline in nature with HNO₃, and that they grew preferentially along the [0 1 2] direction. The emission spectra showed that the LaPO₄:Eu³⁺ samples had the strongest emission intensity when prepared with HNO₃.     

Synthesis and characterization of Mn2O3 nanorods using a novel manganese precursor

The Mn₂O₃ nanorods have been prepared using [Mn(sal)₂] complex as a novel precursor in the presence of sodium dodecyl sulfate (SDS) as surfactant. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectroscopy. Manganese oxide nanocrystals have been prepared under different condition. The controlled experimental results showed that the ultrasonic irradiation and the use of SDS as the surfactant in the chemical process play important role in the formation of the final products.     

Synthesis and characterization of Ag nanorods used for formulating high-performance conducting silver ink

Silver nanorods with ～100?nm in diameter and ～5?µm in length were synthesised by the soft solution-phase approach in the presence of poly(vinylpyrrolidone) (PVP), which was employed as a protecting agent. The obtained silver nanorods were characterised by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-visible spectrum. The molar ratio and injection rate of PVP and AgNO₃ played an important role in controlling the morphology and aspect ratio of nanorods. The growth mechanism of silver nanorods was also discussed. Moreover, the conductive ink was prepared using as-synthesised products, and the electrical resistivity of the final consolidated trace with this kind of ink was up to 2.7?×?10^?5 Ωcm.     

Characterization of Bi2S3 nanorods and nano-structured flowers prepared by a hydrothermal method

Bismuth sulfide nanorods and nano-structured flowers were synthesized by hydrothermal reaction of bismuth nitrate pentahydrate and thiourea solutions, containing 1 and 2 ml of 65% HNO₃, respectively. By using X-ray diffraction (XRD), selected area electron diffraction (SAED), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and high resolution TEM (HRTEM), the products were specified as orthorhombic Bi₂S₃ in the shapes of nanorods and flower-like clusters of nanorods, with the growth of nanorods in the [001] direction. A diffraction pattern was also simulated, and was in good accordance with the SAED pattern obtained from the experiment.     

Fabrication and structure properties of GaN nanowires by ammoniating Ga2O3 films

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.     

Synthesis and characterization of anatase and rutile TiO2 nanorods by template-assisted method

Well-aligned anatase and rutile TiO₂ nanorods and nanotubes with a diameter of about 80–130 nm have successfully been fabricated via sol-gel template method. The prepared samples were characterized by using thermogravimetric (TG) and differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDS). The XRD results indicated that the TiO₂ nanorods were crystallized in the anatase and rutile phases, after annealing at 400–800 °C for different periods of time from 0.2 to 10 h.     

Synthesis of monodisperse shuttle-like α-Fe2O3 nanorods via the EDA-assisted method

Monodisperse hematite shuttle-like nanorods were synthesized successfully by the ethylenediamine (EDA)-assisted method. The structure and morphology were investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectrometer (EDS). XRD studies indicated that the as-prepared product was well-crystallized orthorhombic phase of α-Fe₂O₃. TEM and SEM images showed that the α-Fe₂O₃ nano-particles were of rod shape with an average length of 400 nm and diameter of about 80 nm in the middle part.     

One-step template-free synthesis of ZnWO<Subscript>4</Subscript> hollow clusters

ZnWO₄ hollow clusters made up of nanorods were successfully prepared through a tripotassium citrate assisted hydrothermal process at 180 °C. The hollow clusters’ diameter was about 400 nm, and these clusters were made up of nanorods with a diameter of about 10 nm and a length of about 50 nm. X-ray power diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) were used to characterize the structure and morphology of the synthesized products. Based on experiments, the growth of these hollow clusters followed an aggregation-Ostwald ripening process. The photocatalytic activities for aqueous Rhodamine B of samples were investigated, and it was seen that ZnWO₄ hollow clusters exhibited a strong photocatalytic activity.     

Controlled synthesis of PbWO4 crystals via microemulsion-based solvothermal method

PbWO₄ flowers, nanoribbons and nanorods had been successfully synthesized via microemulsion-based solvothermal method. The products were characterized by power X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The possible mechanisms for the formation of PbWO₄ samples of various morphologies were discussed. Through various comparison experiments, we found that some related experimental parameters including the CTAB concentration, the PVP concentration, the lead ion sources and the solvothermal treating time and temperature had great influences on the product morphology.     

Fabrication of three-dimensional snowflake-like bismuth sulfide nanostructures by simple refluxing

Three-dimensional snowflake-like bismuth sulfide nanostructures were successfully synthesized by simple refluxing at 160 °C in ethylene glycol, using bismuth citrate and thiourea as reactants. The crystal structures and morphologies of the products were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and energy dispersive X-ray spectroscopy (EDX). The Bi₂S₃ nanostructure was built up by highly ordered one-dimensional Bi₂S₃ nanorods, which was aligned in an orderly fashion. Ethylene glycol plays a critical role in the creation of bismuth sulfide three-dimensional nanostructures, which serves as an excellent solvent and structure director. Bismuth citrate, a linear polymer, also makes for the formation of the three-dimensional nanostructures.     

Molten salt synthesis of single-crystal Co3O4 nanorods

The synthesis of the single-crystal Co₃O₄ nanorods by molten salt approach was reported for the first time. The products were characterized by Transmission electron microscopy (TEM), X-ray diffraction (XRD), High-resolution transmission electron microscopy (HRTEM) and Selected-area electron diffraction (SAED). TEM results indicate that these nanorods have diameters of about 150 nm and lengths of about 2 μm. According to the analysis of the SAED and HRTEM results, we drew the conclusion that these nanorods grew along an unusual [− 1,− 1,15] direction by Ostwald ripening mechanism.     

Room temperature synthesis of bismuth oxyfluoride nanosheets and nanorods

At room temperature, two different morphological nanoscaled BiO_xF_3 − 2x (BiOF nanosheets and Bi₂₆O₃₈F₂ nanorods) have been prepared via a simple solution-based route in the presence of diethanolamine (DEA) and NaOH. The compositions and morphologies of bismuth oxyfluoride can be selectively prepared by varying the type of additives. The products were characterized by X-ray diffraction (XRD), energy-disperse X-ray analysis (EDXA), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray photoelectron spectrum (XPS). A possible mechanism was introduced to explain the formation of the products.     

Fabrication of needle-shaped GaN nanowires by ammoniating Ga2O3 films on MgO layers deposited on Si (111) substrates

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.     

Solvothermal synthesis of In(OH)3 nanorods and their conversion to In2O3

In this work, we demonstrate that monodisperse indium hydroxide (In(OH)₃) nanorods constructed with parallel wire-like subunits have been fabricated via a acrylamide-assisted synthesis route without any template. NH₃ from the hydrolysis of acrylamide acts as the OH⁻ provider. The structure and morphology of as-prepared products have been characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and thermogravimetric analysis (TG). A detailed mechanism has been proposed on the basis of time-dependent experimental results. Furthermore, by annealing In(OH)₃ precursors at 500 °C for 3 h in air, In₂O₃ samples were obtained with the designed morphology.