Materials|31 Article(s)
Field Emission of Graphene-angle
WANG Xiao-li, PANG Kai-ge, LIU Wei-hua, LI Xin, TIAN Kang, YIN Yan-nan, and ZHANG Juan
Vertical graphene edge is easy to adsorb gas molecules which affects the stability of field emission. The graphene was transferred to insulation wall structure to get the graphene-angle. The insulation wall structure is made on silicon substrate by inductively coupled plasma etching and the method of wet etching, field emission test was made with graphene-angle as field emission tips, and the field emission characteristics of the graphene-angle and the influence of conductive flow on the field emission were studied. The results show that field emission open field strength of graphene-angle is 9.6 V/μm. Under the anode voltage 2 000 V, when the bias voltage applied on the both sides of the graphene-angle increases from 0 V to 10 V, the field emission current increases from 4.5 μA to 15 μA.
Acta Photonica Sinica
  • Publication Date: Nov. 01, 2014
  • Vol. 43 Issue 11 1116001 (2014)
Luminescence Property in Novel Y3+/Dy3+ Co-doped Bi2ZnB2O7 Phosphors by Assembled Optimal Design
SHI Lin-lin, SUN Jia-shi, ZHAI Zi-hui, LI Xiang-ping, ZHANG Jin-su, and CHEN Bao-jiu
In order to obtain the strongest yellow luminescence intensity of the novel Bi2ZnB2O7: Y3+/Dy3+ phosphor, uniform design and quadratic general rotary unitized design were combined to optimize Y3+/ Dy3+ ions doping concentrations, the result shows that the optimum doping concentrations of Y3+/ Dy3+ were 4.498 mol% and 6.001 mol%, respectively. High temperature solid state method was applied to synthesize the optimal sample, and the crystal structure and luminescent properties were investigated. The emission spectra of the samples under 452 nm excitation were observed, where the blue emission band was at around 460~500 nm, the yellow emission was at around 550~610 nm and the weaker peak of the red emission is at around 650~700 nm. They were corresponding to the emissions from the 4F9/2 excited state to the 6H15/2, 6H13/2 and 6H11/2 ground states, respectively. The result indicates that the Dy3+ ions were located at a non-centrosymmetric site in the host lattice. Besides, the luminescence decay curve illustrated that the fluorescence lifetime of Dy3+ was 0.427 ms. It was found from the comparison between the optimized and the single-doped samples with the same Dy3+ concentration that Y3+-introduction could improve the emission intensity of the studied phosphor in a certain degree.
Acta Photonica Sinica
  • Publication Date: Nov. 01, 2014
  • Vol. 43 Issue 11 1116002 (2014)
The Vibration Spectroscopy and Structures Stability of LinC cluster
LIU Fang, JIANG Zhen-Yi, and ZHANG Chen-Jun
Based on the influence of lithium content in some optical materials to the structure stability and optical proterties,the structure stablility and vibration spectroscopy of carbon-doped clusters LinC(n=1~9) were investigated with density functional theory at the B3LYP/6-31G(d) level.The computed results shown that the structure were three dimension(n>3) structure for LinC except for Li2C and the carbon atom was seen to be trapped in a Li cage.Especially,the electron ground state was found to be a low state for LinC cluster,singlet for n is even while doublet for n is odd.A strong even-odd alternation in the cluster stability appeared in the incremental binding energy,with their n-even numbers being much more stable than the adjacent odd-numbered ones.These parity effects also appeared in the second difference in energy and the gap between HOMO-LUMO.In addition,the dominant channel was losing a Li particle for LinC clusters by analyzing the fragmentation energies.The spectroscopy range of LinC clusters located in fingering area.The vibration frequency of LinC clusters decreased with the increasing of the numbers of Lithium atoms.Moreover,the difference between the lowest and the highest vibration frequency shown maxmium as the number of lithium atoms was odd while it shown minimum as the number of lithium atoms was even.
Acta Photonica Sinica
  • Publication Date: Nov. 01, 2014
  • Vol. 43 Issue 11 1116004 (2014)
Research of Nonlinear Absorption Effect of Pulse Laser Irradiation for GaAs
ZHOU Hai-jiao, SUN Wen-jun, and LIU Zhong-yang
In order to research nonlinear absorption effect of pulse laser irradiation for GaAs,a physical model of Gaussian distribution pulse laser irradiation for semiconductor material was established by software COMSOL Multiphysics. The thermal effects of semiconductor material GaAs was analyzed under irradiation of nanosecond pulse laser with wavelength of 1064nm. The temperature distribution along radial direction and longitudinal direction of semiconductor material GaAs was calculated under irradiation of nanosecond pulse laser with different power density by means of solving the thermal conduction equations. The contribution of one-photon absorption, two-photon absorption and free carrier absorption to temperature of the irradiated material was discussed. The calculation results show that when the pulse laser power density is above 1010W/cm2, Free Carrier Absorption played a leading role and is more than that of One-Photon Absorption of material. When the pulse laser power destiny is below 108 W/cm2, the temperature contribution of two kinds of nonlinear absorption of materials could be ignored. The result is basically consistent with relevant experiments, which shows that physical model constructed is scientific.
Acta Photonica Sinica
  • Publication Date: Nov. 01, 2014
  • Vol. 43 Issue 11 1116005 (2014)
Vapor Etching Method for Diamond Wire Sawn Multicrystalline Silicon Wafers
LIU Xiao-mei, CHEN Wen-hao, LI Miao, and ZHOU Lang
Vapor etching was used to etch diamond wire sawn multicrystalline silicon wafers. The vapor was produced from 2 g silicon wafer adding into HF-HNO3-H2O acid mixture solution (400 mL, in the volume ratio of 6: 3: 1) to reaction at room temperature. Diamond wire sawn multicrystalline silicon wafers were etched in vapor. Etching for 4 min, saw marks can be removed and honeycomb etched pits were densely covered with silicon wafer surface. The reflectivity of silicon wafer decreases remarkablely by using the vapor etching methods. The reflectivity of the silicon wafers by vapor etching is low to 19.51%. The micro-roughness of diamond wire sawn mulicrystalline silicon wafers etched with vapor method is actually about 20% higher than that of etching with traditional acid mixture solution method.
Acta Photonica Sinica
  • Publication Date: Nov. 01, 2014
  • Vol. 43 Issue 11 1116006 (2014)
Study and Fabrication of the Dual Band-pass in Grain Screening System
FU Xiu-hua, HE Song-lin, JIA Xing-ming, LIU Dong-mei, ZHANG Jing, and LIU Shuang
Optical sorting of grain, is using different characteristics of near infrared absorption spectra of impurity inferior food and high quality food, and based on the difference of feature band which reflects the test components in the spectrum to do the sieving grain. Before the light beam into the sensor, it needs to pass through the optical filter,filtering the multiple test band and reducing the noise effect. A dual band-pass optical filter was developed which is the core parts in the system, it is based on the film system design theory, adopt Smith method and the film system design software basing on the combination of period and non period multilayer coatings to design the dual band-pass filter coating,. Utilize electron beam evaporation and ion assisted deposition method to prepare and mathematical modeling to analyze, which has reduced the influence of experimental error to the spectrum and prepared the filter coating. The average transmittance of which is more than 97% in 1 200 nm and 1 450 nm band and less than 1% in 1 000~1 130 nm and 1 130~2 000 nm band. The film meets the use requirements through the test system and evaluation.
Acta Photonica Sinica
  • Publication Date: Dec. 01, 2014
  • Vol. 43 Issue 12 1216001 (2014)
Effect of Ca-doping on the Formation and Electrical Property of CuCrO2 Films
HU Bing, CHUAI Ya-hui, FU Yang, LI Ya-dan, SHENG Hong-zhi, ZHANG Hong, YANG Yue, and WANG Yi-ding
CuCrCaO2 films were prepared by sol-gel.The effect of Ca-doping on the formation and electrical properties of the films with different environments and annealing temperatures was investigated.The CuCr1-xCaxO2(x=0,0.01,0.03,0.05,0.07)films are annealed at 1 100 ℃ in N2,XRD shows at low Ca concentration, the films have good crystallinities,lattice constant a,c and average grain size n increase with Ca concentration;at high Ca concentration impurity phases generate,makes a,c,n smaller,the results are identical with X-ray Diffraction(XRD).Besides,3%Ca hierarchical-mixed-spin-coating films are annealed quickly with different temperatures in air and N2 respectively.XRD shows hierarchical-mixed-spin-coating leads CuCrCaO2 to single crystal growth in N2 and has more obvious preferred orientation with higher annealed temperature.Using Hall instrument to measure films’ electrical properties with different Ca concentrations. The best conductivity is 1.22×10-1S/cm when x=0.03,which is three orders of magnitude higher than not doped films.It is shown that Ca doping helps to improve and the conductivity,the corresponding carrier mobility is 1.77 × 1018 cm-3,which means the material is P type structure.
Acta Photonica Sinica
  • Publication Date: Dec. 01, 2014
  • Vol. 43 Issue 12 1216002 (2014)
The Preparation of TiO2/Eu3+,Y3+ Down-conversion Film and Its Application in Dye-sensitized Solar Cells
NIE Ming-qi, HU Zhi-qiang, ZHANG Lin-an, QIN Yi-ying, LIU Gui-shan, and HAO Hong-shun
TiO2/Eu3+,Y3+ down-conversion film was prepared by Sol-Gel method and applicated in dye-sensitized solar cells. Ultraviolet light converted to visible light by down-conversion feature to improve the visible light intensity of dye-sensitized solar cells. TiO2/Eu3+,Y3+ powder were characterized by the X-ray diffraction and fluorescence spectroscopy, the TiO2/Eu3+,Y3+ down-conversion film were tested by the fluorescence spectroscopy and ultraviolet-visible spectrophotometer. Exposed to 396 nm ultraviolet light, down-conversion film could emit 535~620 nm wavelength visible light which showed a down-conversion features of the film. Bilayer down-conversion film still kept a higher visible light transmittance compared with a single phase TiO2 film. When total rare earth content is 4%, short circuit current is increased by 21.5% and photoelectric conversion efficiency by 14.1% with down-conversion feature of TiO2/Eu3+,Y3+ film.
Acta Photonica Sinica
  • Publication Date: Dec. 01, 2014
  • Vol. 43 Issue 12 1216003 (2014)
Ionized Donor Bound Exciton States in Strained Wurtzite ZnO/MgxZn1-xO Disk-shaped Quantum Dots
ZHENG Dong-mei, and WANG Zong-chi
Within the framework of the effective-mass approximation, the binding energy, optical transition energy, oscillator strength, and radiative lifetime of ionized donor bound exciton (D+X) in a Quantum Dot (QD) were calculated, assumed that the ionized donor was located at the disk axis, the disk-shaped QD consisted of a finite length cylinder of ZnO material surrounded by MgxZn1-xO. The calculations were performed by using a suitable variational wave function for finite confinement potential at all surfaces, including the strong built-in electric field effect due to the spontaneous and piezoelectric polarizations. Calculated results reveal that the disk structural parameters (height and Mg composition in the barrier) and the donor position have a strong influence on the binding energy, optical transition energy, oscillator strength, and radiative lifetime of (D+X) complex. As the disk height increases, the binding energy, optical transition energy, and oscillator strength both decrease, whereas the radiative lifetime increases. The influences of disk height on the binding energy, optical transition energy, oscillator strength, and radiative lifetime become more prominent for the QDs with higher Mg composition. The binding energy (the optical transition energy) has a maximum (minimum) when the donor is located in the vicinity of the left interface of the QDs. On the contrary, the binding energy (the optical transition energy) has a minimum (maximum) when the donor is located in the vicinity of the right interface of the QDs.
Acta Photonica Sinica
  • Publication Date: Jan. 01, 2015
  • Vol. 44 Issue 1 116001 (2015)