Xue Cheng-Shan

Thermal Decomposition Behaviour of Zn3N2 Powder

Thermal gravimetric analysis (TGA) and differential thermal analysis (DTA) are employed to investigate the thermal decomposition behaviour of zinc nitride powder, which indicated that the thermal oxidation of zinc nitride powder in air follows the two-step reaction model. When the temperature is between 200 and 500 degrees C, compact ZnO or ZnxOyNz layers in the surface of zinc nitride powder will begin to form, and prevent the interior of zinc nitride powder from the thermal oxidation. When the temperature is higher than 500 degrees C, fast thermal oxidation occurs in the interior of zinc nitride powder. Over 750 degrees C, all the zinc nitride will turn into zinc oxide. The x-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) of the zinc nitride powder annealed at different temperature in air are consistent with the two-step reaction model.

Fabrication of GaN Nanorods in a Large Scale on Si(111) Substrate by Ammoniating Technique

GaN nanorods in a large scale have been synthesized on Si (111) substrates by ammoniating Ga2O3/Mg films under flowing ammonia atmosphere at the temperature of 1000?C for 15?min. The as-synthesized GaN nanorods are characterized by scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy. The results demonstrate that these straight nanorods are hexagonal wurtzite GaN single crystals in diameters ranging from 200?nm to 600?nm.

Synthesis of large-scale GaN nanowires by ammoniating Ga2O3 films on Co layer deposited on Si(111) substrates

A mass of GaN nanowires has been successfully synthesized on Si(111) substrates by magnetron sputtering through ammoniating Ga 2 O 3 /Co films at 950 C. X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscope and Fourier transformed infrared spectra are used to characterize the samples. The results demonstrate that the nanowires are of single-crystal GaN with a hexagonal wurtzite structure and possess relatively smooth surfaces. The growth mechanism of GaN nanowires is also discussed.更多还原A mass of GaN nanowires has been successfully synthesized on Si(111) substrates by magnetron sputtering through ammoniating Ga2O3/Co films at 950°C. X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscope and Fourier transformed infrared spectra are used to characterize the samples. The results demonstrate that the nanowires are of single-crystal GaN with a hexagonal wurtzite structure and possess relatively smooth surfaces. The growth mechanism of GaN nanowires is also discussed.

Synthesis of flower-shape clustering GaN nanorods by ammoniating Ga2O3 films

Flower-shape clustering GaN nanorods are successfully synthesized on Si(111) substrates through ammoniating Ga2O3/ZnO films at 950°C. The as-grown products are characterized by x-ray diffraction (XRD), scanning electron microscope (SEM), field-emission transmission electron microscope (FETEM), Fourier transform infrared spectrum (FTIR) and fluorescence spectrophotometer. The SEM images demonstrate that the products consist of flower-shape clustering GaN nanorods. The XRD indicates that the reflections of the samples can be indexed to the hexagonal GaN phase and HRTEM shows that the nanorods are of pure hexagonal GaN single crystal. The photoluminescence (PL) spectrum indicates that the GaN nanorods have a good emission property. The growth mechanism is also briefly discussed.

Fabrication of Mn-Doped GaN Nanobars

We report a new method for large-scale production of GaMnN nanobars, by ammoniating Ga2O3 films doped with Mn under flowing ammonia atmosphere at 1000° C. The Mn-doped GaN sword-like nanobars are a single-crystal hexagonal structure, containing Mn up to 5.43 atom%. Thickness is about 100 nm and with a width of 200–400 nm. The nanobars are characterized by x-ray diffraction, scanning electron microscopy, x-ray photoelectron spectroscopy, high-resolution transmission electron microscopy and photoluminescence. The GaN nanobars show two emission bands with a well-defined PL peak at 388 nm and 409 nm respectively. The large distinct redshift (409 nm) are comparable to pure GaN(370 nm) at room temperature. The red-shift photoluminescence is due to Mn doping. The growth mechanism of crystalline GaN nanobars is discussed briefly.

Fabrication of Syringe-Shaped GaN Nanorods

Syringe-shaped GaN nanorods are synthesized on Si(111) substrates by annealing sputtered Ga2O3/BN films under flowing ammonia at temperature of 950°C. Most of the nanorods consist of a main rod and a top needle, looking like a syringe. X-ray diffraction and selected-area electron diffraction confirm that the syringe-shaped nanorods are hexagonal wurtzite GaN. Scanning electron microscopy and high-resolution transmission electron microscopy reveal that these nanorods are as long as several micrometres, with diameters ranging from 100 to 300 nm. In addition to the BN intermediate layer, the proper annealing temperature has been demonstrated to be a crucial factor for the growth of syringe-shaped nanorods by this method.

Fabrication and Characterization of Mg-Doped GaN Nanowires

Mg-doped GaN nanowires have been synthesized by ammoniating Ga2O3 films doped with Mg under flowing ammonia atmosphere at 850° C. The Mg-doped GaN nanowires are characterized by x-ray diffraction (XRD), scanning electron microscope (SEM), high-resolution transmission electron microscopy (HRTEM) and photo-luminescence (PL). The results demonstrate that the nanowires are single crystalline with hexagonal wurzite structure. The diameters of the nanowires are 20–30 nm and the lengths are 50–100 μm. The GaN nanowires show three emission bands with well-defined PL peak at 3.45 eV, 3.26 eV, 2.95 eV, respectively. The large distinct blueshift of the bandgap emission can be attributed to the Burstein–Moss effect. The peak at 3.26 eV represents the transition from the conduction-band edge to the acceptor level AM (acceptor Mg). The growth mechanism of crystalline GaN nanowires is discussed briefly.

Growth of β-Ga2O3 nanorods by ammoniating Ga2O3/V thin films on Si substrate

This paper reports that β-Ga2O3 nanorods have been synthesized by ammoniating Ga2O3 films on a V middle layer deposited on Si(111) substrates. The synthesized nanorods were confirmed as monoclinic Ga2O3 by x-ray diffraction, Fourier transform infrared spectra. Scanning electron microscopy and transmission electron microscopy reveal that the grown β-Ga2O3 nanorods have a smooth and clean surface with diameters ranging from 100 nm to 200 nm and lengths typically up to 2μm. High resolution TEM and selected-area electron diffraction shows that the nanorods are pure monoclinic Ga2O3 single crystal. The photoluminescence spectrum indicates that the Ga2O3 nanorods have a good emission property. The growth mechanism is discussed briefly.

Preparation of GaN Nanorods by Rare Earth Metal Tb Catalyst-Assisted Process

Abstract Rare earth metal Tb was employed as the catalyst to prepare GaN nanostructures. GaN nanorods were synthesized through ammoniating Ga 2 O 3 /Tb films sputtered on Si(111) substrates. Results of X-ray diffraction (XRD) and Fourier transform infrared spectrum (FTIR) indicate that the prepared nanorods are hexagonal GaN. Observations of scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) show that the GaN nanorod is single-crystalline in structure with 80∼200 nm in diameter and several tens of microns in length. The growth mechanism of GaN nanorods was also discussed briefly.

Optical and Micro-structural Properties of GaN Nanowires by Ammoniating Ga2O3/Nb Films

Abstract Single-crystalline GaN nanowires have been synthesized on Si(111) substrates by magnetron sputtering through ammoniating the Ga 2 O 3 /Nb films at 900 °C in a quartz tube. The as-prepared nanowires 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). Transmission electron microscopy (TEM) shows that the GaN nanowires are straight and smooth, and possess the diameters of about 50 nm and lengths up to several microns. When excited by 325 nm helium-cadmium (He-Cd) laser light at room temperature, the GaN nanowires only have a strong ultraviolet luminescence peak located at 367 nm, owing to GaN band-edge emission. Finally, the growth mechanism of GaN nanowires is discussed briefly.