最新刊期
卷 15 ， 期 3 ， 1994
- 摘要：The nitrogen doped p-type ZnSe on (100) GaAs substrates has been grown by atmospheric pressure (AP) metal organic chemical vapour deposition (MOCVD).Pure NH3 gas was used as a doping material.The nitrogen doping level was controlled by the NH3 gas flow rate.Because sticking coefficients of NH3 molecules appear to be very low,the NH3 flow rate must be great enough to provide sufficient doping of N.This leads to cause degradation of the epilayer quality.Above result is clearly indicated by measurements of X-ray diffraction and photoluminescence(PL).Obtaining of p-type conduction in ZnSe is evidenced by measuring optical and electrical properties of N-doped ZnSe layers.At the low doping level, the PL spectrum exhibited a dominant free-to-acceptor transition (FA) emission at 460um and also exhibited deep centre emission at 580um.ZnSe layers with a low doping level have a very high resistivity.It was difficult to determine theconduction type due to a large Hall-voltage drift.Both band intensities increased with increasing NH3 flow rate.The results indicate that the shallow acceptor and deep centre levels were formed by doping nitrogen.In the high doping level, the 77K PL of the epilayers is dominated by the deep centre emission at 580urn and the bands broadened.The ZnSe layer clearly indicated a p-type conduction by Hall measurements at room temperature.Hall mobilities is nearly 46cm2/V·s and carrier concentrations reach the order of 1016cm3.The p-ZnSe/n-GaAs heterojunctions exhibit good rectification properties.The forward-bias turn-on voltage is 1.5V.The results confirmed the p-typeconduction of the N-doped ZnSe layers with a high doping level.关键词：MOCVD;p-type ZnSe;photoluminescence;hall measurements119|69|0更新时间：2020-08-11
- 摘要：In this paper,the transport process of the gas reactants for growth of, Ⅲ-Ⅴ compounds in MOCVD system has been analyzed.It is given that the mass quantity entered into the reactor of the MOCVD dependes on the structure of the MOCVD and on thecharacter of the reactants.As a result, the transport of the gas reactants in MOCVD systerm is determind not only by the carry of the carry gas but also by the concentration diffusion of the reactants.So that, the mass quantity of the reactants entered into the reactor of the MOCVD is much more than the data calculated in term of carry principle.Accoding to the theory analysis,the calculated formula has been obtained.It gives the dependence of the transported mass quantity of the reactants on the structure ofMOCVD,on the flowes and diffusion coeficient of the gas.Using this formula,some experimental phenomina can be expiated:why the Ⅴ/Ⅲ ratio grwon, Ⅲ-Ⅴ compouds has to be higher than the chemical component of the materials,why the Ⅴ/Ⅲ ratio reported by different papers were different data and why the different apparture used different Ⅴ/Ⅲ ratio to grow same materials.关键词：MOCVD;epitaxial growth;Ⅴ/Ⅲ ratio;calculated deviation140|82|0更新时间：2020-08-11
- 摘要：High quality strained quantum well, with photoluminescence FWHM of 4.3nm at 10K only 3.49meV, is obtained by MOCVD technology.Based on studies of low temperature spectra of several InGaAs/GaAs strained quantum well samples as function of excitation intensity and temperature, we conclud that the inhomogeneity of the exciton energy caused by composition fluctuation in the well, being the greatest contributors to inhomogeneous broadening, is the major problem to be solved during MOCVD processing.The experimental results also indicate that the migration of carriers to low-energy sites in the fluctuation potentials should be considered when we study the photoluminescence line shapes of excitons in quantum wells.关键词：photoluminescence;strained quantum well;MOCVD104|105|0更新时间：2020-08-11
- 摘要：This paper reports studies on luminescent processes of BaFCl0.5Br0.5:Sm2+, which is a typical inorganic material of hole-burning.By measuring the dependence of fluorescent intensities and the decay of 5D2,5D1,5D0→7F0 transition, a mode has been proposed to discribe the process of thermal activation of 5D2→4f5d, nonradiative transition between 5DJ and radiative transition of 5DJ→7F0.关键词：radiatitransition;nonradiative transition;thermal activation103|66|5更新时间：2020-08-11
- 摘要：The thermoluminescence (TL) of BaFxCl2-x:Eu2+ Phosphors under X-ray irradiation at the different temperature has been reported.The dependence of the temperature of TL peaks on the kinds of defects was obtaind, meanwhile the difference of TL of BaFxCl2-x:Eu2+ (x=0.90, …,1.15) under X-ray irradiation at two temperature was also discussed.关键词：X-ray irrddiation;thermoluminescence136|62|0更新时间：2020-08-11
- 摘要：Concerning electron transition probability of7F0→5D2 of Sm2+ in BaFClxBr1-x:Sm2+ system, the excitation spectra of 4f5d bands, the decay dependence of 5D2→7F0transition on the composition (x) and temperature, absorption probability of7F0→5D2and emission transition probability of 5D2→7F0 are investigated.The results show that the 4f5d bands of Sm2+ become lower and closer to 5D2 states with the increase of Br concentration in BaFClxBr1-x:Sm2+ system.Therefore, it could be expected that the holeburning efficiency of these materials should increase with the increase of Br concentration.关键词：hole-burning efficiency;electron transition probability;absorption cross section100|41|1更新时间：2020-08-11
- 摘要：It is difficult to adjust the relative spectral sensitivity S (λ) of photo-detector to exactly match to the CIE standard photometric observer-the spestral luminous efficacy V (λ) due to the difference of relativ spectroal rdistributians among the different phosphors, therefore, it is needed to carry out the color-correction in the measurements both for the relative brightness of phosphors and other photometricquantities.In this work,we calculated color-correction coefficient of relative brightness of some phosphors.关键词：phosphor;relative brightness;color-correction coefficient;relative spectral sensitivity;relative spectral power distribution119|87|0更新时间：2020-08-11
- 摘要：Photovoltaic properties of single and double layer structural organic thin film electroluminescent devices have been firstly reported.The polarity of photovoltaic indicated that the photovoltaic effect was Schottky effect.And different semiconductor contactsbetween different organic semiconductors or organic materials and electrodes of the devices have been given by analysing the action spectra of pbotocurrent of devices.In thesingle layer device(ITO/Alq3/Al),the photocurrent was generated from Alq3/Al interface, which implied that there was a Schottky barrier here.For double layer device (ITO/diamine/Alq3/Al), the photocurrent was generated from both Alq3/Al and diamine/Alq3 interfaces.This comfirmed that a p-n junction exists at the interface of diamine/Alq3, which had been assumed in prior paper.It is the p-n junction that confines the carriers and the excitons in a narrow luminessent layer and increases the EL efficiency and brightness in double layer device.Energy band models were proposed to explain the photovoltaic behaviors and the EL charactoristics of the devices.102|108|2更新时间：2020-08-11
- 摘要：The values of third-order susceptibilitiesX(3) of porphyrin-phthalocyanine heterodimers have been measured by degenerate four-wave mixing (DFWM) method.The third-order susceptibilies X(3) of the heterodimers are more than that of free base porphyrin (H2TTP) and phthalocyanine (H2Pc), the X(3) values of porphyrin-phthalocyaine heterodimers first increase directly proportional to the chain length between porphyrin and phthalocyalocyanine (Xn=3(3) >Xn=2(3)).The X(3) value reaches the largest when the chain length equal the number of the 3 methylene.Then the X(3)) values of heterodimers decrease (Xn=3(3)>Xn=4(3)>Xn=5(3)) even though the chain lengths increase further.These results are related to flexible chains which are covalently-linked porphyrin and phthalocyanine.We give a tentative explanation for these results.关键词：porphyrin-phthalocyanine heterodimers;third-order optical susceptibility;DFWM105|43|2更新时间：2020-08-11
- 摘要：A new system consisting of 9,10-dimethoxyanthracene (DMA)as donor and anthraquinone (AQ) as acceptor linked by bisphenol A (BA) or hydroquinone (OP) has been synthesized.Intramolecular exciplex for mation was demonstrated by fluorescence spectroscopy.The influence of mutual orientation of the two chromophores and effects of solvent on intramolecular exciplex formation were discussed.117|46|1更新时间：2020-08-11
- 摘要：The SrC8H4O4:Tb phosphor was prepared by the solution reaction method, and its thermal stability was examined.The powder X-ray diffraction and electron diffraction patterns were obtained.The SrC8H4O4:Tb crystal is a monoclinic, space group P21/n.Its lattice parameters were calculated to be α=1.4192, b=0.8018, c=1.3223nm,β=100.25 deg.The UV absorption, emission and excitationspectra were investigated.The energy transfer mechanism from C8H4O4 radical to Tb3+ ion was discussed.Underultraviolet excitation, the C8H4O4 radical is raised to singlet Sл,л1* and Sn, л1* excita tion states, it then decays from the tow states through intersystem crossing to triplet states Tл, л1* and T n, л1*, respectively.The Tл, л1* state in the energy corresponds to 5D4 enerty level of Tb3+ ion, so that the excitation enrtgy is very easily transferred to Tb3+ion to result in very strong 5D4-7F, emission.The T n, л1* state can transfer the energy to Tb+3ion, can also directly return to ground state by emitting blue fluorescence.98|52|10更新时间：2020-08-11
- 摘要：This paper reports the research on enhancement of light emission by the peroxidase catalyzed luminolhydrogen peroxide reaction.We synthesized enhancer p-iodophenol for experiments of enhance chemiluminecent reaction, and tested enhancing light emissioneffects of enhancer in the reaction.It is demonstrated that the enhanced chemilumi nescent reaction can reduce the lowest determination concentration of peroxidase to 10-12～10-13mol /L.关键词：enhancement;luminol;p-iodophenol130|74|2更新时间：2020-08-11
- 摘要：The paper reported experimental study of determination for ANT using Enzymelinked Immunosorbent Assay-Chemiluminescence (ELISA-CL) methods.Dilution of used rabbit anti-ANT antiserum was 1/500～1/10-4.The detectable range for ANT was 0～10μg/ml.关键词：ELISA-CL;ANT;TNT102|74|0更新时间：2020-08-11
- 摘要：We propose a new method of measuring both the nonlinear refractive index and the nonlinear absorption coefficient using transmission spectum for the first time.We show theoretically that the two parameters can be obtained from the linear and nonlinear transmission spectra of the medium and the distribution function of the dye laser frequency.The method requires very simple experimental apparatus.The nonlinear refractive indices and the nonlinear absorption coefficient and their sign can be obtained from the experimental results in the relatively large wavelength range.We can get two wavelengths at the nonlinear refraction and absorption maximums.We have obtained both thenonlinear refractive index and the nonlinear absorption coefficient as a function of the wavelength for ZnSe-ZnS multiple quantum wells on transparent CaF2 substrate at 77K.108|53|0更新时间：2020-08-11
- 摘要：C60 LB films with 30 layers were deposited on Ag-Na ion exchange glass waveguide.Ar+ laser pulses were coupled into the waveguide by prism coupler and limitation of output power was observered.124|55|0更新时间：2020-08-11
- 摘要：Four kinds of 8-hydroxyquinoline rare earth chelate are synthseased and employed as the emitters in organic thin film electroluminescence (OTFEL) cells, respectively.Their characteristics of current density-voltage (I-V) and EL spectra are studied.It is found that the emitting spectra are wide band (the half width is about 100nm),instead of the special emitting spectra from the rare earth ions.In addition, by analysingthe tendency of EL emitting intensity with the other metal chelates of 8-hydroxyquinoline and its derivative in previous reports.It is suggested that the EL brightness of 8-hydroquinoline chelates containing light metals is higher than that of 8-hydroquinoling chelates containing heavy metals.100|63|9更新时间：2020-08-11
- Address：No.3888 Dong Nanhu Road, Changchun, Jilin, China Postal code：130033
- Tel：0431-86176862 Email：fgxbt@126.com
- Technical support is provided by Beijing Founder electronics co., LTD 吉ICP备11002662号-17
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0