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ABSTRACT: High-density well-aligned ZnO nanorods were successfully synthesized on ZnO-buffer-layer coated indium phosphide (InP) (100)
substrates by a pulsed laser deposition (PLD) method. Scanning electron microscopy images show that the ZnO buffer layer formed
uniform drip-like structure and ZnO nanorods were well-oriented perpendicular to the substrate surface. The sharp diffraction
peak observed at 34.46° in X-ray diffraction scanning pattern suggests that the ZnO nanorods exhibit a (002)-preferred orientation.
The PL spectra of ZnO samples shows a strong near band edge emission centered at about 380 nm and a weak deep level emission
centered at around 495 nm, and it demonstrates that the ZnO nanorods produced in this work have high optical quality, which
sheds light on further applications for nanodevices.
Science in China Series G Physics Mechanics and Astronomy 04/2012; 52(2):207-211. · 1.41 Impact Factor
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ABSTRACT: CdS
x
Se1−x
quantum dots were fabricated by a simple spin-coating heat volatilization method on InP wafer. Temperature dependent photoluminescence
of CdS
x
Se1−x
quantum dots was carried out in a range of 10–300 K. The integrated photoluminescence intensity revealed an anomalous behavior
with increasing temperature in the range of 180–200 K. The band gap energy showed a redshift of 61.34 meV when the temperature
increased from 10 to 300 K. The component ratio of S to Se in the CdS
x
Se1−x
quantum dots was valued by both the X-ray diffraction data and photoluminescence peak energy at room temperature according
to Vegard Law. Moreover, the parameters of the Varshni relation for CdS0.9Se0.1 materials were also obtained using photoluminescence peak energy as a function of temperature and the best-fit curve: α = (3.5 ± 0.1)10−4 eV/K, and β = 210 ± 10 K (close to the Debye temperature θ
D of the material).
KeywordsCdS
x
Se1−x
-quantum dots-temperature dependent photoluminescence
Science China: Physics, Mechanics and Astronomy 04/2012; 53(10):1842-1846. · 0.78 Impact Factor
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Kaitong Sun, Heqiu Zhang,
Lizhong Hu,
Dongqi Yu,
Shuangshuang Qiao,
Jingchang Sun,
Jiming Bian,
Xi Chen,
Lingxuan Zhang,
Qiang Fu,
Ziwen Zhao
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ABSTRACT: Ultralong ZnO piezoelectric-fine-wires (PFWs) with a perfect hexagonal structure have been prepared by an upstream growing chemical vapor deposition (CVD) method. Furthermore, isolatable and flexible piezoelectric strain sensors based on individual ZnO PFWs have been fabricated by a simple and reliable technique. The whole device was fully packaged by epoxy polymeric resin (EPR). The I–V characteristic of the isolatable sensor is highly sensitive to the strain applied on it, which was well interpreted in terms of variation in Schottky barrier height (SBH) caused by strain induced band structure change and piezoelectric effect. The sensor exhibited excellent stability and fine reversibility, and a remarkably high gauge factor up to 1010 had been achieved. It is expected that the isolatable and flexible piezoelectric strain sensor demonstrated here will have applications in detection of external mechanical forces, as well as electromechanical switch with a high ON/OFF ratio.
Physica Status Solidi (A) Applications and Materials 10/2009; 207(2):488 - 492. · 1.46 Impact Factor
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ABSTRACT: Novel phosphorus-doped and undoped single crystal ZnO nanotetrapods were fabricated on sapphire by a simple chemical vapour deposition method, using phosphorus pentoxide (P2O5) as the dopant source. The optical properties of the samples were investigated by photoluminescence (PL) spectroscopy. Low-temperature PL measurements of phosphorus-doped and undoped samples were compared, and the results indicated a decrease in deep level defects due to the incorporation of a phosphorus acceptor dopant. The PL spectrum of the phosphorus-doped sample at 10 K exhibited several acceptor-bound exciton related emission peaks. The effect of phosphorus doping on the optical characteristics of the samples was investigated by excitation intensity and temperature dependent PL spectra. The acceptor-binding energies of the phosphorus dopant were estimated to be about 120 meV, in good agreement with the corresponding theoretical and experimental values in phosphorus-doped ZnO films and nanowires.
Journal of Physics D Applied Physics 02/2009; 42(5):055110. · 2.54 Impact Factor
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ABSTRACT: ZnO thin films were prepared on quartz glass, Si (100), and sapphire (001) substrates by a chemical vapour transport (CVT) technique. During the growing processes, the source and substrate temperatures were maintained at 1000 °C and 600 °C, respectively. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) measurements showed that the crystalline qualities of ZnO thin films were sensitively dependent on substrates. ZnO thin film deposited on sapphire substrate exhibited the best morphology with the largest crystallite size of more than 20 μm. Meanwhile, the XRD patterns showed that ZnO thin film deposited on sapphire substrate was strongly c-axis preferred-oriented with high crystalline quality. The optical properties of ZnO thin films were investigated by photoluminescence (PL) spectroscopy at room temperature (RT). The results suggested that the optical properties of ZnO thin films were highly influenced by their crystalline qualities and surface morphologies.
Materials Letters. 63(2):316-318.
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ABSTRACT: The temperature dependence of the photoluminescence full width at half maximum and the Huang–Rhys S factor is investigated in ZnO/Mg0.15Zn0.85O superlattices. The coupling strength between excitons and longitudinal–optical phonons, which calculated from the temperature dependence of the photoluminescence full width at half maximum, is closely related to the exciton binding energies when the wellwidth is small.
Materials Science in Semiconductor Processing 10(6):287-290. · 0.75 Impact Factor
