Abstract: It is very desirable to grow ZnO epitaxial films on Si substrates since Si wafers with a high
quality is available and their prices are quite low. Nevertheless, it is not easy to grow ZnO films epitaxially
on Si substrates directly because of formation of an amorphous SiO2 layer at the interface of ZnO
and Si. A Zn film and an undoped ZnO film were deposited sequentially on an (100) Si substrate by rf
magnetron sputtering. The sample was annealed at 700°C in a nitrogen atmosphere. X-ray diffraction
(XRD), photoluminescence (PL) and atomic force microscopy (AFM) analyses were performed to
investigate the cristallinity and surface morphology of the ZnO film. According to the analysis results the
crystallinity of a ZnO thin film deposited by rf magnetron sputtering is substantially improved by using a
Zn buffer layer. The highest ZnO film quality is obtained with a 110nm thick Zn buffer layer. The surface
roughness of the ZnO thin film increases as the Zn buffer layer thickness increases.
Abstract: Laser dyes perylene red (p-red) or pyrromethene 567 (p567) were co-doped with coumarin 440
(C440) or coumarin 500 (C500) into MTES- and VTES-derived organically modified silicates
(ORMOSILs) by sol-gel process. The effects of coumarin dye concentration on the laser performances of
p-red and p567 were investigated. The results from laser efficiency measurements illustrated that at
optimized coumarin concentration, the slope efficiency of co-doped p-red increased by a factor of 2 while
that of co-doped p567 increased marginally. It was also found that by co-doping coumarin, the laser
wavelength of p-red blue shifted and the laser thresholds for p567 and p-red could be reduced. The energy
transfer mechanisms involved were also discussed.
Abstract: ZnO thin films were grown on single-crystal Si(100) substrate by pulsed laser deposition (PLD)
technique. The crystal structure and electrical properties were investigated as a function of oxygen partial
pressure. Results indicate that highly c-axis oriented ZnO films can be obtained at all oxygen pressure
range. With the increase of oxygen pressure, the crystallinity is further enhanced and the film presents
smooth, uniform and dense packed columnar microstructure. Hall measurement indicates the resistivity
of ZnO films increases with oxygen pressure. ZnO film grown at optimum conditions is employed to
fabricate the MSM structured UV detectors with Ti/Pt/Au interdigital electrode configuration by standard
photolithography and lift-off technique. The I-V characteristic and photo response measurement indicate
a good ohmic contact between the ZnO film and electrode, and significant photoresponsivity under
Abstract: ZnO thin films were deposited on sapphire (α-Al2O3) substrates by RF magnetron sputtering at
substrate temperatures of 500, 600, 650 and 700°C for 3h at rf-powers ranging from 60 to 120 W. The
FWHM of the XRD (0002) peak for the ZnO film was reduced down to 0.07° by optimizing the chamber
pressure at a substrate temperature of 700°C. Sharp near-band-edge emission was observed in the
photoluminescence (PL) spectrum for the ZnO film grown at room temperature. Excess RF power
aggravates the crystallinity and the surface roughness of the ZnO thin film. Pole figure, AES and PL
analysis results confirm us that RF magnetron sputtering offers ZnO films with a lower density of
crystallographic defects. ZnO films with a high quality can be obtained by optimizing the substrate
temperature, RF power, and pressure of the RF magnetron sputtering process.
Abstract: ZnO:Eu3+ films were obtained by dip-coating method and influence of heat treatment on
luminescent properties was investigated. Emission and excitation spectra revealed that the organic and
nitrate molecules, which adhered on the surface of films when the samples were treated at lower
temperatures (300oC-400oC), played an important role on the luminescent properties. At higher
temperatures (500oC-800oC), the luminescence spectra of ZnO and Eu3+ were quite different with those
treated at lower temperatures. Energy transferred from ZnO host to Eu3+ was obviously observed in the
emission and excitation spectra. The luminescence mechanism was discussed briefly.
Abstract: ZnO films were deposited on Si (100) substrate by ultrasonic spray pyrolysis at atmosphere.
The film grown at optimum conditions is well crystallized with uniform, smooth and dense microstructure.
Photoluminescence measurement shows a strong near band edge UV emission at 379nm and an
almost undetectable deep-level emission band centered at 502nm. The resistivity of ZnO film is reduced
by an order after N-In codoping, which produces p-type conduction with high hole concentration and hall
Abstract: Y2O3:Eu3+ thin film was synthesized by sol-gel method with inorganic salt raw materials, and
the crystal structure and luminescent properties were investigated. By adding organic additive to the sol, a
homogeneous film with high luminescent intensity could be obtained by dip-coating technique on the
surface of alumina sheet and quartz glass. Structures of the films were studied by XRD and SEM. The
excitation spectra of the films showed a wide excitation peak from 200nm to 260nm, and the emission
spectra had a strongest emission peak at 611nm which revealed a close relationship with the calcining
Abstract: The phosphors of MO-Re2O3-B2O3:Eu3+ (M = Mg, Sr; Re = Y, Gd) were prepared by
conventional solid-state reaction. Red-emitting MO-Re2O3-B2O3:Eu3+ (M=Mg, Sr; Re=Y, Gd) phosphors
had the highest luminescence intensity under vacuum ultraviolet (VUV) excitation. They had sharp
emission peak lines at 591 and 613nm, which were assigned to the transitions of 5D0→7F1 and 5D0→7F2.
By the introduction of Sr into MgO-Re2O3-B2O3:Eu3+ (M=Mg, Sr; Re=Y, Gd), the intensity of absorption
peaked at 172nm and the emission peak intensity were enhanced.
Abstract: Ti,Eu co-doped Y2O2S:0.06Ti,0.08Eu phosphor with red long afterglow emission from Eu ions
was synthesized via traditional sintering method. Results showed that sintering temperature has great
influence on the crystal structure, luminescence and afterglow property of the phosphors. The best luminescence
and afterglow properties were obtained for the phosphors sintered at 1200°C for 2.5h. Furthermore,
only emissions originated from charge transition of Eu3+ was found in the luminescence spectra
whereas the afterglow spectra were composed of two sets of emissions: a broad yellow emission band
around 565nm and a group of narrow peaks in the wavelength range above 530 nm. The origin of
afterglow spectra was discussed: the former is likely related to emission from Ti related traps and the
latter is supposed to come from the Eu3+ through an energy transfer process from Ti emission to Eu3+.