-
[show abstract]
[hide abstract]
ABSTRACT: Dendritic ZnMgO nanostructures were synthesized on Si(111) substrates by a catalyst-free thermal evaporation method using Zn and Mg powder as the source materials. The structural, compositional and optical properties were investigated by field emission scanning electron microscopy, x-ray diffraction, transmission electron microscopy, Raman scattering and photoluminescence. The results indicate that the incorporated Mg in the as-grown nanostructures mainly form a separated cubic MgO phase. By annealing in oxygen, hexagonal ZnMgO can be formed with the dendritic nanostructures maintained, which exhibits a blueshift of ~0.05 eV in the near band edge emission. It is possible to tune the Mg content in the nanostructures simply by varying the distance between the substrate and the source materials.
Journal of Physics D Applied Physics 08/2006; 39(17):3764. · 2.54 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Al-doped quasi-aligned ZnO submicro-rods were prepared on heavily doped n-type Si(111) substrates by the thermal evaporation method. Electrical transport measurements indicate the Al-doped ZnO submicro-rods have better conductivity than the undoped submicro-rods. The photoluminescence excitation spectrum of the annealed sample indicates an energy level ~100 meV below the conduction band minimum, which may be due to the localized state of the Al impurity. The annealed sample exhibits a strong green emission centred at 2.45 eV that can be seen by the naked eye and an infrared emission centred at 1.10 eV. The intensity ratios of the deep-level green emission to the ultraviolet emission are 0.86 and 30 for the as-grown and annealed samples, respectively. Moreover, two emissions at 2.2 and 1.96 eV were discriminated from the PL spectrum of the as-grown Al-doped ZnO submicro-rods, which were not observed in the pure ZnO submicro-rods and the annealed Al-doped sample.
Journal of Physics D Applied Physics 06/2006; 39(13):2696. · 2.54 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Quasialigned ZnMgO ternary nanorods with sharp single-crystal tips were prepared by using thermal evaporation without a catalyst. The growth process included two steps: the formation of ZnO droplets and then the formation of ZnMgO nanorods. The obtained ZnMgO nanorods with abruptly sharpened tips crystallized well as hexagonal phase, with preferred orientation along the c axis. The nanorods are about 200 nm in diameter and the tips are 50 nm. With the Mg incorporation, the ultraviolet near-band-edge emission shows a clear blueshift. The possible growth mechanism of the ZnMgO nanorods is discussed.
Applied Physics Letters 03/2006; 88(11):113106-113106-3. · 3.84 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Zn0.84Mg0.16O and Zn0.12Mg0.88O nanowires with different morphology have been synthesized by a catalyst-free thermal evaporation method using Zn and Mg metals as the raw materials. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), and room-temperature photoluminescence (PL) measurements were used to determine the structure and optical properties of the obtained products. The obtained nanowires have diameters in a range of 30 nm-80 nm, crystallized well as hexagonal and cubic phase, with preferred orientation along the c-axis and a-axis for the two samples of Zn0.84Mg0.16O and Zn0.12Mg0.88O, respectively. Room-temperature PL at wavelengths of 384.4 and 495.8 nm has been observed for the sample of Zn0.84Mg0.16O. Upon annealing in Ar ambient, the emission peaks in PL spectra show a clearly blue shift.
The Journal of Physical Chemistry B 01/2006; 109(50):23930-4. · 3.70 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Radial and quasi-aligned ZnO nanorod arrays were prepared on Si(111) substrates by a simple vapor phase method using Zn and zinc acetate dihydrate (ZA) as the source materials. X-ray diffraction, field emission scanning electron microscopy, Raman scattering and photoluminescence were used to characterize the structural and optical properties of the obtained nanostructures. The growth mechanisms of the two kinds of ZnO nanostructures were discussed based on the growth conditions. The different decomposing rate of the ZA plays an important role in the initial nucleation of ZnO nanorods.
Materials Letters. 61:1170-1173.
