最新刊期
卷 29 ， 期 1 ， 2008
- 摘要：On the condition of electron-LO phonons weak coupling, the properties of exciton in parabolic quantum dot are studied. By using the linear combination operator and unitary transformation method, the ground state energy and the mean number of optical phonons in a parabolic quantum dot are calculated for the weak coupling exciton case. Numerical calculations are performed for GaAs semiconductor as a example and the results show that the mean number of optical phonons of weak-coupling exciton decrease with the increasing of the ground state energy and the confinement strength of quantum dot and increase with the increasing of the quantum dot radius.The ground state energy decrease with the increasing mean number of optical phonons and the coupling strength.关键词：quantum dot;exciton;mean number of optical phonons;weak-coupling115|95|1更新时间：2020-08-11
- 摘要：The ground state energy of weak-coupling polaron in a parabolic quantum dot considering the phonon dispersion is calculated using the squeezed-state variational approach. The variational approach we applied is based on two successive canonical transformations and using a single-mode squeezed-state type unitary transformation to deal with the bilinear terms which we neglected usually. The relations of the ground-state energy of polaron in a parabolic quantum dot on the electron-LO-phonon coupling constant, the coefficient of phonon dispersion and the confinement length are derived in the electron-LO-phonon weak-coupling case.关键词：phonon dispersion;squeezed-state;quantum dot;polaron115|110|2更新时间：2020-08-11
- 摘要：In this paper, the energy levels of polarons in the wurtzite GaN/AlxGa1-xN quantum well structure are studied by using Lee-Low-Pines (LLP) transition. The ground state, first excited state and transition energies from first excited state to ground state are calculated as a function of well width (L) and depth (V0). The results indicate that the ground state, first excited state and transition energies rapidly decrease with increasing the well width at smaller L, but slowly at larger L, and finally approach to the bulk value of GaN. The ground state, first excited state and transition energies all slowly increase with increasing V0, and it is more visible in narrow well. It is also found that the contribution of electron-phonon interaction in wurtzite nitride quantum well structure is very large, the value (about 40 meV) is much larger then that (about 3 meV) in zinc-blende (GaAs/AlxGa1-xAs) quantum well structure. Therefore, the contribution of electron-phonon interaction in wurtzite GaN/AlxGa1-xN quantum well structure should be considered when the problem of election state is discussed.关键词：nitride quantum well;polaron;ground state energy;transition energy105|75|0更新时间：2020-08-11
- 摘要：In recent years, with the quick development of nanofabrication technology to material, the physical characteristics of low dimensional material have aroused great interest. The lots of novel effects of the quantum dots systems have attracted more and more physicists. Because of the wide device applications and a lot of new optical properties and electron transport characteristics in such structures, understanding the electronic properties of these systems is of particular importance. Many investigators studied the properties of bound polaron in a quantum dot in many aspects by a variety of theoretical and experimental methods. Recently, the properties of polaron in asymmetric quantum dot have been studied by using the linear combination operator and the unitary transformation methods by the present authors. However, using linear combination operator method, the properties of bound polaron in an asymmetries quantum dot has not been investigated so far. In this paper, influences of the transverse and longitudinal effective confinement length of quantum dot, the coulomb bound potential and the electron-phonon coupling strength on the properties of weak-coupling bound polaron in an asymmetries quantum dot were studied. We obtain an expression for the vibration frequency and the ground state energy of the weak-coupling bound polaron in an asymmetries quantum dot as a function of the transverse and longitudinal effective confinement length of quantum dot, the coulomb bound potential and the electron-phonon coupling strength by using a linear combination operator and the unitary transformation method. Numerical calculations were performed and the results show that the vibration frequency and the ground state energy of the weak-coupling bound polaron in an asymmetries quantum dot will strongly increase with decreasing the transverse and longitudinal effective confinement length, and will increase with increasing the coulomb bound potential and decreasing the electron-phonon coupling strength.关键词：asymmetric quantum dot;bound polaron;linear combination operator;effective confinement length86|69|0更新时间：2020-08-11
- 摘要：Single crystal sapphire (Al2O3) samples were irradiated by 208Pb27+ ions with energy of 230 MeV to the fluences ranging from 2×1012 to 5×1014 ions/cm2 and subsequently annealed at 600, 900 and 1100 K temperature. The modification of structure and optical properties induced by ion irradiation were analyzed using photoluminescence(PL)and Fourier Transform infrared(FTIR)spectra measurements. The PL measurements showed that absorption peaks located at 390 nm and 450 nm appeared in irradiated samples, the PL intensities reached up to the maximum for the sample irradiated with the fluence of 1×1013 ions/cm2. The peak of 380 nm became very intensive after 600 K anneal and other peaks are very weak. After annealing at 900 K,the peak of 380 nm weaken and 360 nm, 510 nm peak start buildup, the peak of 380 nm entirely vanished and 360 nm, 510 nm peak increasing along with annealing temperature at 1100 K. From the obtained FTIR spectra, it was found that Pb-ion irradiation induced broadening of the absorption band in 460~510 cm-1 and position shift of the absorption band in 1000~1300 cm-1 towards to high wavenumber. Those indicated that the vibration structure affected by Xe ion irradiation. The possible mechanism of damage in single crystal sapphire induced by irradiation was briefly discussed.关键词：Al2O3;heavy ion irradiation;anneal;PL spectra104|94|1更新时间：2020-08-11
- 摘要：Organic light-emitting devices (OLEDs) with PBD electron-transporting layer were fabricated. The effect of PBD electron-transporting layer on the spectrum of the devices was investigated by doping PBD in NPB or DCJTB. The spectra of two devices are different from each others. Due to PBD layer transfer parts of the electrons to the layer of NPB, electrons meet holes in NPB and emit blue light. Especially, there are four peaks in the spectrum of device (3). By the method of Gaussian fitting it should be ascribed to the emissions of NPB, Alq3, DCJTB and exciplex which occurs at the interface between NPB and PBD:DCJTB. The formation of the exciplex is analyzed.关键词：PBD;electron-transporting layer;exciplex;organic light-emitting devices (OLEDs)112|76|5更新时间：2020-08-11
- 摘要：A new EL material, [N,N′-bis(salicylidene)-ethylenediamine] zinc [Zn(salen)] was synthesized and characterized. Zn(salen) exhibits high thermal stability, excellent thin film forming ability. Its HOMO, LUMO and electrochemical band gap were estimated to be-5.87 eV,-3.41 eV, and 2.46 eV by cyclic voltammetry, respectively. Zn(salen) powder exhibits bright blue emitting, but Zn(salen) film exhibits yellow emitting under radiation of 365nm. The device ITO/CuPc/NPD/Zn(salen)/Al could emit yellow light. The EL peak was at about 552 nm with CIE coordinates of x=0.504, y=0.316. The device has a turn-on voltage of about 7.5 V and a maximum brightness of about 301 cd/m2. The current efficiency is about 1.6 cd/A.关键词：Zn(salen);Electroluminescent material;preparation;characterization110|164|2更新时间：2020-08-11
- 摘要：In the last few years, organic electroluminescent devices (OLEDs) have been the subject of increasing interest due to their potential impact on lighting industry and back lighting application. In order to optimize the device structure and explore the marketable OLEDs, researchers are synthesizing high performance emitting materials with desirable properties. So far, many new materials with RGB (red, green, blue) emission have been developed to meet this requirement. However, in contrast to green-light-emitting materials, blue-light-emitting materials still need to be further improved in performance. In this paper, two blue-light-emitting materials, Ca(Ⅱ) complex of aromatic N, O-chelate ligand, namely Ca(BTZ)2 and Ca(BTZ)2phen [BTZ:2-(2-hydroxyphenyl)benzothiazolate, phen:1,10-phenanthroline], were synthesized and charac-terized by FT IR and UV-Vis absorption spectra. Their energy band, photoluminescent property, and film-forming ability were investigated by UV-Vis absorption spectra, cyclic voltammetry, atomic force microscope, and photoluminescent spectra. The results show that the UV-Vis absorption bands of Ca(BTZ)2 are located at about 290, 330 and 422 nm, while, UV-Vis absorption bands of Ca(BTZ)2phen are located at 292, 330 and 428 nm. The 290 nm or 292 nm bands, which are S0→S1 transition, are attributed to the local π→π* transition of the deprotonated ligands. The broad bands of 330 nm can be assigned to a phenoxido-to-thiazolyl π→π* transition. The bands of 422 nm or 428 nm, which correspond to the transition of HOMO to LUMO, are mainly caused by the charge transition from electron donor O to electron acceptor N. The optical gap, the energy of the highest occupied orbital (EHOMO), and the energy of the lowest unoccupied orbital (ELUMO) of Ca(BTZ)2 are 2.79, 5.74 and 2.95 eV, respectively. The values of optical gaps, EHOMO and ELUMO of Ca(BTZ)2phen are 2.77, 5.8 and 3.03 eV, respectively. The increased degree of conjugation by introducing phen reduced the value of optical gap of Ca(BTZ)2phen. Ca(BTZ)2 powder emited blue fluorescence with peak wavelength at 458 nm and 500 nm. PL spectrum maximum peak wavelengths of Ca(BTZ)2phen were located at 465 nm and 514 nm. Ca(BTZ)2phen formed compact film by vacuum vapor deposition. Ca(BTZ)2 and Ca(BTZ)2phen were found to be potentially excellent broad-band blue photoluminescent materials.关键词：bis[2-(2-hydroxyphenyl)benzothiazolate]calcium;bis[(2-hydroxyphenyl)benzothiazolate-(1;10-phenanthroline)]calcium;optical properties;white-light emitting101|80|4更新时间：2020-08-11
- 摘要：The microcavity OLED with a 100 nm-thick highly reflective Al top cathode and a 22 nm-thick semitrans parent Ag bottom anode on a glass substrate was fabricated. With MoO3 and LiF as efficient hole and electron injection layers, respectively, the microcavity OLED show a turn on voltage of 2.5 V and a high luminance above 15000 cd/m2 at 10 V, with a maximum efficiency of around 6 cd/A, which is 2 times that of the conventional OLEDs. The optical characteristics of the microcavity, such as narrowed and viewing angle dependent spectra, were examined.关键词：OLEDs;high efficiency;microcavity110|179|3更新时间：2020-08-11
- 摘要：A organic light-emitting diode device with a structure of ITO/PEDOT:PSS/MEH-PPV/Al was fabricated. High electric field is applied vertically to the surface of the sample to polarize the PEDOT:PSS layer during the process of spin-coating. Due to the electric-field induced orientation of the PEDOT:PSS,the device with an appropriately treated PEDOT:PSS film as hole-injecting buffer layer exhibited significantly enhanced luminescence and decreased driving voltage. The results suggest that the electric field-induced orientation is useful for the improvement of device performance. And the polarized MEH-PPV layer exhibits a low resistance compared to the unpolarized layer. By looking at the PEDOT: PSS fabrication steps, it can be inferred that a gradient enrichment of negative PSS content can form at the top surface due to the attractive power of the external electric-field. This should aid charge injection into the MEN-PPV by gradually increasing the work function from the ITO surface to the MEN-PPV surface giving a graduated barrier to hole-injection.关键词：molecular orientation;electroluminescence;hole-injection112|76|4更新时间：2020-08-11
- 摘要：In recent year, organic electroluminesence (EL) has attracted much attention because of its potential applications in large area full color flat panel displays. Organometallic complexes, which have five-or six-membered ring structures, with high stability, high melting point and high fluorescence quantum efficiency, are widely applied in organic EL devices. Organometallic complexes formed with imidazole, benzimidazole or pyridyl benzimidazole as small molecular ligand have attracted widespread attentions because of their high photoluminescence and electroluminesence officiency. In this paper, a new light emitting material 2,6-bis(benzimi-dazol-2-yl)pyridine-zinc acetate was synthesized. Its structure and optical properties were investigated by FT-IR spectra, UV-Vis absorption spectra, fluorescence excitation spectra and emitting fluorescence spectra. Its energy band and light emission mechanism were discussed. Results show that 2,6-bis(benzimidazol-2-yl)pyridine-zinc acetate is a tridentate ligand light emitting material. Its infrared spectra show relatively high intensity band at about 1 606 cm-1. This band is typical of the benzimidazole ring conjugated C=N stretching vibration, which shifts to lower frequency related to the free ligand.The pyridine ring conjugated C=N stretching vibration at 1620 cm-1, it also shifts to lower frequency related to the free ligand. Its UV absorption bands are at 346 nm and 366 nm, which can be assigned to nitrongen→zinc charge transfer.The complexe in N,N-dimethylformamide emitted intensive blue fluorescence with peak wavelength of 458 nm and its powder form also emitted intensive blue fluorescence with peak wavelength of 475 nm under UV irradiation.Its optical gap was estmated about 3.01 eV. Its fluorescence is chiefly attributed to the long wavelength excitation band. The complexe is expected to find applications in organic electroluminesence diodes through appropriate design.关键词：(benzimidazole-2-yl)pyridine;structure;optical properties103|93|1更新时间：2020-08-11
- 摘要：Intense research activities are currently being undertaken on organic light-emitting devices.Because of their potential applications in flat panel displays and solid state lightening.Light-emitting materials for these devices can be divided into two general classes,those are fluorescent and phosphorescent materials. Phosphorescent light emitting devices are particularly interesting for being able to utilize all the injected charges for emission.Heavy-metal complexes in which strong spin-orbit coupling leads to singlet-triplet state mixing can result in high efficiency electrophosphorescence in organic light-emitting devices(OLEDs).In this report, devices using red phosphorescent dye Ir(pig)2(acac) as dopant and BAlq as host are fabricated.The structure of the device is ITO/NPB(30 nm)/Ir(piq)2(acac):BAlq(25 nm)/BCP(13 nm)/Alq3(35 nm)/LiF(1 nm)/Al(1000 nm). All of the films are fabricated by thermal deposition way onto a precleaned ITO-coated glass substrate (sheet resistance 50 Ω/□) at a background pressure <2×10-4 Pa. The deposition appartus is Edward Auto-500 Thermal Evaporation Coating System.The thinkness of the deposited films is monitored by an oscillating quartz thickness monitor.The electroluminescence(EL) spectra, brightness and CIE coordinates of the devices are recorded with Spectra Scan PR-650(Photo Research).The brightness-current density,voltage versus current density are measured by a OLEDs testing system,comprosing of a 2400 Sourcemeter(Keithley) and a 485 Picoammeter(Keithley).All the measurements are carried out at room temperature.We change the doping concentration in the host material.When the doping concentration reaches 8%, the commission internationale de’Eclairage (CIE) coordinates of the device are (x=0.67,y=0.32), which are close to meet video display standards.The device reaches the highest brightness 9 380 cd/m2 at voltage 16 V. The external quantum efficiency reaches 5.7% at the current density 5.45 mA/cm2.Because of the short phosphorescent life of the Ir(piq)2(acac),the external quautum efficiency is still as high as 4.7% at the current density of 100 mA/cm2.Futher study shows that both the short range Dexter energy transfer mechanism and the direct dopant dye trap exist simultaneously.关键词：phosphorescent dye;triple-state;energy transfer;T-T annihilation99|88|1更新时间：2020-08-11
- 摘要：The EL intensity and the spectrum of the PET films were tested under dc high electric fields by home-made experimental set-up. The result shows that the light emissio intensity of the PET films increases along with the electric fields; the pre-breakdown field is about 4.00 MV/cm. The EL spectra have emission peaks at 300~400 nm, 400~460 nm, 500~600 nm and 680 nm, the peaks between 500 nm and 600 nm is higher. The peak of 680 nm increases quickly after the pre-breakdown phenomenon appears. In order to value the dielectric character of the PET films, the experimental data were analyzed by the analysis of two-parameter Weibull distribution, the life time, the cumulative failure probability of the breakdown field and the reliability equation were found out under the voltage power increased step by step at (24±1)℃. After the verification of assumption, it’s found that the experimental results submit Weibull distribution.关键词：poly(ethylene terephthalate);electroluminescence;Weibull distribution;reliability129|143|1更新时间：2020-08-11
- 摘要：Organic electroluminescent device has become a study hotspot in flat panel display and illuminance fields. In this technology, the design and synthesis of materials are the core, studies on their properties in relation to organic electroluminescence are critical. Schiff base complexes have attracted much attention recently due to their potential application in electroluminescent displays,since the first report on Schiff bases metal complexes organic light-emitting devices (OLEDs) in 1993. Salicylaldehyde has been acted as an usually used reactant in this type of materials. It’s well-known that if an electron-donating group is introduced into a conjugated structure, the photoluminescence efficiency can be enhanced significantly, so a modified method of preparing Schiff bases was used here by the introduction of —OCH3 to starting material salicylaldehyde. On the other hand, much effort has been devoted to the design and synthesis of boron-containing compounds for their potential applications in functional materials, including OLEDs. Boron is strongly electrophilic by virtue of its tendency to fill the vacant orbital and form 8-coordinated complex, so in contrast to other organometallic compounds, organoboron compounds are in general more stable owing to the increased covalency of B—O and B—N bonds. In this paper, a new Schiff base organoboron complex as an organic electroluminescence material was synthesized by the reaction of ethylenediamine o-vanillin Schiff base (HMOB)2en [N,N′-bis(2-hydroxy-3-methoxybenzaldehyde) ethylenediamine] and B(Ac)3 in absolute toluene. It was characterized by 1H NMR, 13C NMR and infrared absorption. Photoluminescence and ultraviolet-visible absorption spectra analysis were also conducted. 1H NMR, 13C NMR and infrared absorption spectra indicate that the complex is a complex with the molecular formula of [B(MOB)2en]Ac. The luminescence of [B(MOB)2en]Ac was realized by the introduction of B, which strengthened the rigidity of the molecule and decreased the non-radiation transition, finally gave a strong blueish-green-emitting luminescent emission. The peak position of light-emitting is at 485 nm, with a FWHM (Full Width at Half Maximum) of 87 nm, CIE coordinates x=0.2211 and y=0.4172. The optimum excitation wavelength is 378 nm.关键词：Schiff base;boron complex;spectra of fluorescence99|155|3更新时间：2020-08-11
- 摘要：The steady-state fluorescence and time-resolved fluorescence spectra properties of bisphthalocyanines terbium chloroform solution were investigated. The influences of excitation wavelength and concentration on the spectral properties were discussed. The experimental results indicated that the bisphthalocyanines terbium chloroform solution have strong fluorescence emission peaked at 707 nm. And it corresponds to the electrons’ transition from excitation states S1 to ground states S0. With the different excitation wavelength, the intensity of emission spectra has a large change, but the position of emission peak does not change. The fluorescence emission peak at 707 nm of bispthtalocyanine terbium has two component lifetimes, the short-lifetime belongs to monomer, and long-lifetime belongs to H-aggregation. Along with the reduction of concentration, the proportion of monomer will increase, and the proportion of short-lifetime will increase too.关键词：bisphthalocyanine terbium;spectra of fluorescence;lifetime of fluorescence105|143|1更新时间：2020-08-11
- 摘要：Amplified spontaneous emission(ASE) from the structure comprised of a poly(2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylene vinylene) (MEH-PPV) film deposited on SiO2 was reported.The change of the emission spectra detected from the edge of the sample showed a clear threshold and gain narrowing phenomenon when increasing the excitation intensity.With increasing the thickness of the polymer film,the threshold of ASE diminishes and the net gain increases.A maximum net gain of 25.03 cm-1 and a minimum threshold of 2.2 μJ/pulse are obtained at the thickness of 150 nm.Our results indicate that MEH-PPV is an attractive gain medium in optically pumped polymer lasers and amplifier.关键词：MEH-PPV;polymer film;amplified spontaneous emission117|103|2更新时间：2020-08-11
- 摘要：Trapping centers and transfer process of electrons and holes in infrared stimulable phosphors XS:Ra,Sm (X=Sr, Ca; Ra=Ce, Eu) were investigated in the photo-stimulated luminescence. The difference of infrared absorption spectra before and after excitation exhibits the same shape as the infrared stimulation spectra, with several notches cut by the absorption lines of Sm3+ 4f-4f transition on the broad band. This suggests that each of the electron-trapping centers is adjacent to a Sm3+ ion, and thus the fact that Sm ions keep in +3 valence without being changed into Sm2+ in the trapped state. Further more, electron paramagnetic resonance measurements show that the EPR absorption from Eu2+ in SrS:Eu,Sm remains unchanged after excitation in comparison with the spectrum before excitation. It can be speculated that even the Eu2+ ions are not changed into Eu3+ during the trapping process. Different from the covalent Ⅲ-Ⅴ semiconductors, in the ionic crystals such as alkali-earth sulfides, the carriers are trapped by the defects instead of by the doped impurity ions. In the case of several kinds of luminescent center, the stimulated luminescence is dependent on the preceding excitation wavelength that determined which centers being excited and thereby binding the holes left by the excitation of electrons into the conduction band.关键词：carrier capturing;electron trap;hole trap;photo-stimulated luminescence;EPR106|105|0更新时间：2020-08-11
- 摘要：The NaCaPO4:Tb3+ green phosphor applicable for UVLED chip was synthesized by the general high temperature solid-state reaction and its luminescence properties were investigated. It shows six major emission peaks locating at 420,442,492,545,584 and 620 nm, which correspond to the 5D3→7F5, 5D3→7F4, 5D4→7F6, 5D4→7F5, 5D4→7F4 and 5D4→7F3 typical transition of Tb3+, respectively. The most intense peaks located at 492 nm and 545 nm and the phosphor shows excellent green emission. The excitation spectra contain a weak broad band extending from 200 to 280 nm and two peaks at 330~390 nm, which correspond well with the emission of UVLED (350~410 nm). The effects of doped-Tb3+ concentration and charge-compensating of Li+, Na+ and K+ on the emission intensity were also investigated. It shows that the optimum doped-Tb3+ concentration is 10% and Li+ gives the best improvement to enhance the intensity of the emission. The NaCaPO4:Tb3+ is a potential green-emitting phosphor for white light emitting diode (W-LED).关键词：luminescence;phosphor;NaCaPO4：Tb3+;LED101|111|9更新时间：2020-08-11
- 摘要：Under the excitation of 980 nm laser and 808 nm laser, the upconversion luminescence of ZBLAN:Yb3+,Tm3+ is detected. The mol fraction of Yb3+,Tm3+ is 3% and 1%, respectively. The emission of ZBLAN:Yb3+,Tm3+ is blue light with the peak at 476 nm which comes from 1G4→3H6 transition of Tm, no matter excited by 980 nm, 808 nm and both 980 nm and 808 nm, but the emission intensity is different. The emission intensity co-excited by both 980 nm and 808 nm is much stronger than that excited by 980 nm or 808 nm only. This phenomenon can be explained by luminescence mechanism. Under the excitation of 980 nm or 808 nm, the emission of 476 nm is three photon or two photon process, respectively, while in the 980 nm and 808 nm co-excitation system, the emission of 476 nm is due to one photon process.123|91|3更新时间：2020-08-11
- 摘要：Eu3+-doped YxTi1-xO1-0.5x crystal film was spin-coated on quartz glass substrates through sol-gel route. The structure and luminescence properties of the resultant film were investigated by X-ray diffraction (XRD) and fluorescence spectrometer, respectively. The results of XRD revealed that the film was made up of YxTi1-xO1-0.5x grains with cubic structure in average size about 17 nm. Typical Eu3+ emission peaks were observed and the strongest emission with red color corresponds to the 5D0→7F2 transition. UV xenon lamps, excimer lasers and mercury lamp are powerful excitation sources for Eu3+ visible fluorescence in the Eu3+-doped YxTi1-xO1-0.5x crystal film.关键词：europium;yttrium titanate;crystal film;red emission96|134|3更新时间：2020-08-11
- 摘要：A new red phosphor Eu3+ doped La2Mo2O9 have been prepared by high temperature solid state method at 850℃ and the structure and luminescent properties of this phosphor were investigated. The XRD patterns show that single cubic phase La2Mo2O9 crystal is synthesized in this experiment. The luminescent properties were studied by the excitation and emission spectra. The excitation spectra are composed of a broad band and a series of narrow bands; the excitation spectra include many narrow bands, which attribute to the intrinsic transition from 7FJ (J=1~4) to 5DJ (J=0, 1) of Eu3+. The results indicate that this phosphor can be excited by UV light of 395 nm and visible light of 470 nm, also emit red light at about 620 nm. The luminescent intensity of this phosphor is more than 1.5 times of that of Y2O2S:Eu3+, thus it can be used as red phosphor in the system of UV-LED based and blue-LED based white LED. The effects of Eu3+ molar concentration and flux on the luminescence properties were studied in this paper. The results show the intensity will reach the strongest when the molar concentration of Eu3+ is 30%; the NH4Cl is the appropriate flux and its most suitable mass fraction is 3%.关键词：La2Mo2O9：Eu3+;solid-state method;white LED111|115|10更新时间：2020-08-11
- 摘要：The emission of Er3+ around 1.54 μm in silicate host matrices drives great interest as this wavelength corresponds to the minimum attenuation in silica-based optical fibers (third window). High density ions implantation would cause much defect in silicate host matrix. In our study, erbium doped glass was prepared by ions implantation method with the density of 3×1016 cm-2. These samples were annealed at temperature from 773 K to 1273 K for 1 hour. They were characterized with Raman spectra, X-ray photoelectron spectra (XPS), absorption spectra, and photoluminescence spectra (PL). In our experiment, visible and infrared luminescence from Er3+ and a broad defect-related luminescence were observed. At room temperature, the strongest PL intensity from Er3+ was observed for the sample annealed at 1173 K. The intensity of the 558 nm emission decreases with increasing temperature, while the intensity of the 537 nm line actually peaks at 300 K. This effect is explained based on the thermalization of electrons between the two closely spaced energy levels. A fortuitous temperature dependence of the 4S3/2 levels to the 4I15/2 ground state was discovered. The intensity of the 4S3/2 line increases with increasing temperature below 180 K, then decreases from 180 K to room temperature, which can be attributed to energy transfer from Er3+ to SiO2 defect.关键词：SiO2;defect;PL spectrum;energy transfer98|92|0更新时间：2020-08-11
- 摘要：The phosphors of 2SrO·0.25B2O3·0.75P2O5:RE3+ (RE=Ce,Tb)were synthesized by high temperature solid state reaction. The luminescence properties of Ce3+, Tb3+, the sensitization of Ce3+ to Tb3+and dynamics of them were studied. The results indicate that the brightness for the5D4→7F5 green emissions of Tb3+in the phosphor of Ce3+and Tb3+ co-doped 2SrO·0.25B2O3·0.75P2O5, corresponding to Ce3+excitation greatly increased in comparison with that in single Tb3+ doped samples. As the concentration of Tb3+varies from 1% to 8%, the energy transfer efficiency between Ce3+ and Tb3+ reaches to as high as 70%. The present results demonstrate that in the phosphor of Ce3+and Tb3+ co-doped 2SrO·0.25B2O3·0.75P2O5 efficient energy transfer exists. The Ce3+ and Tb3+ co-activated 2SrO·0.25B2O3·0.75P2O5 powders can possibly be applied as the newly developed green efficient phosphors in the field of lighting and display.131|97|2更新时间：2020-08-11
- 摘要：Y2O3:Ln nanocrystals with different Ln3+(Ln=Eu or Tb) doping concentrations and average sizes were prepared by chemical self-combustion. And the bulk materials of corresponding doping concentrations were obtained by annealing at high temperature. The emission spectra, excitation spectra and X-ray diffraction spectra of Y2O3:Ln nanocrystals and bulk materials were measured. The research indicated that under the effect of quantum confinement effect and surface effect, the Y2O3:Eu charge transfer band red-shifted clearly while the particle size decreased. Furthermore, the charge transfer band of the small size particles (8 nm) clearly broadened towards the long wavelength, this was attributed to the increase of the amount of Eu3+ ions existing in low crystallization degree environment close to the surface. The study also indicated that the shape of excitation peaks (bands) corresponding to the 4f5d transition absorption of Tb3+ in the excitation spectra of Y2O3:Tb nanocrystals changed a lot with the variety of the particle size. This is because that the Tb3+ ions exist in two very different local environments:the low crystallization degree environment close to the surface and the high crystallization degree environment inner the particles. The absorption peaks of 4f5d transition were different in the two environments. The Tb3+ ions ratio in the two environments changs with the variety of the particle size. So the intensity of corresponding excitation peaks (bands) changed and the shapes of the excitation spectra changed. By comparing the excitation spectra of different doping concentrations, it can be found that with the increase of Tb3+(or Eu3+) concentrations, the relative strength of the Y2O3 exciton transition absorption excitation peak to the 4f5d transition (or charge transfer band) excitation peak decreased. The excitation efficiency of Y2O3 exciton absorption band is very low when the doping concentrations of the luminescent centers were higher. But the excitation efficiency of Y2O3 exciton absorption band increased when the doping concentrations were quite low.关键词：Y2O3：Ln(Ln=Eu or Tb)nanomaterials;UV excitation;surface;exciton absorption124|54|9更新时间：2020-08-11
- 摘要：As a new generation of long afterglow phosphors, rare earth doped aluminates are drawing more and more attention. However, though the blue and the green phosphors with excellent afterglow performance are put into commercial use, the red afterglow phosphor doped with Dy3+ or Tb3+ suitable for illuminating is still dissatisfied with the white afterglow phosphor. We developed a new way to meet the conditions of red afterglow phosphor: aluminates doped with Mn4+.Following this new method, we synthesize LiAl5O8:Mn4+,Li5AlO4:Mn4+, LiAlO2:Mn4+,and find that the former two have red long afterglow, this have not been reported before, then the luminescent properties of the two kinds of materials were studied, the reason of different intensity in different hosts was pointed out. We also test the intensity-concentration curve, notate that the radiation of Mn4+ is due to transition of 2E→4A2, its emission spectrum is a broad band, peaked at 675 nm. It absorb ultraviolet strongly, the excitation spectrum extends from 620 nm to 770 nm, At last we research the mechanism of long afterglow of these materials, discuss why the long afterglow properties are different between these kinds of materials.关键词：LiAl5O8;Li5AlO4;LiAlO2;Mn4+red long afterglow132|149|7更新时间：2020-08-11
- 摘要：As a new generation of long afterglow phosphors, rare earth doped alkaline earth silicates and aluminates are drawing more and more attention. However, though the blue and the green phosphors with excellent afterglow performance are put into commercial use, the white afterglow phosphor suitable for illuminating is dissatisfying. Recently, a novel method of achieving stable white afterglow through combination of different coloured emissions from single activator, such as Dy3+ or Tb3+, was developed.Following this new method, a series of Dy3+-doped calcium magnesium silicate phosphors: CaMgSi2O6:Dy3+, Ca2MgSi2O7:Dy3+, and Ca3MgSi2O8:Dy3+ with white long-lasting afterglow were prepared and investigated. The characteristic intra-configurational 4f emissions of Dy3+ were observed in the emission spectra as well as the afterglow spectra under ultraviolet excitation. The combination of the 480 nm blue emission corresponding to the 4F9/2→6H15/2 transition and the 575 nm yellow emission corresponding to the 4F9/2→6H13/2 transition yielded white-light emission. The white-coloured afterglow emission can last more than 1 hour for the most of the samples under study. The concentration dependence of the ratio of the yellow emission intensity to blue emission intensity was also examined and found to be varied for the different host. The thermoluminescence spectra above room temperature are employed for the discussion of the origin of the traps and the mechanism of the persistent luminescence. The calcium magnesium silicate hosts doped with Dy3+ are promising candidates for the development of the white long afterglow materials, although the refinements of the materials and further investigation are needed.关键词：white light;long afterglow phosphor;luminescence;CaMgSi2O6：Dy3+;Ca2MgSi2O7：Dy3+;Ca3MgSi2O8：Dy3+109|105|2更新时间：2020-08-11
- 摘要：ZnO films were grown on Si substrates by using plasma-assisted metal-organic chemical vapor deposition (MOCVD) method. Low-temperature ZnO buffer layers deposited on Si substrates were used as intermediate layers for the growth. The samples were investigated by X-ray diffraction, Scanning electron microscope and photoluminescence (PL) spectra. It is discovered that the low-temperature buffer layer can reduce the lattice distortion caused by lattice misfit and difference of the thermal expansion coefficients. With a low-temperature grown ZnO buffer layer, the X-ray diffraction (XRD) of the ZnO film results a strong (002) diffraction peak. The full-width at half-maximum (FWHM) of the (002) ZnO peak becomes narrower and the value of it declines from 0.21° to 0.18°. Meanwhile, the PL spectra peak value of the sample at room temperature increases obviously. The crystal quality and optical properties of the ZnO films which are deposited at 610℃ on low-temperature buffer layer are improved significantly.关键词：ZnO thin film;metal-organic chemical vapor deposition (MOCVD);low-temperature grown ZnO buffer layer;XRD;SEM122|82|1更新时间：2020-08-11
- 摘要：p-type MgxZn1-xO film was grown on semi-insulating GaAs substrate by metal-organic chemical vapor deposition. The arsenic atoms, which acted as the acceptors in the film, were diffused from the substrates when the film was annealed in oxygen ambient at 700℃. And the cause of formation about p-type film was also discussed. The measurements, such as the XPS, HALL, XRD and PL were carried out. The existence of As in the film was proved by XPS. The resistivities and carrier concentrations of the film were measured by HALL effect measurement and the effect of anneal in the oxygen on them were discussed. The (002) peak in the XRD pattern and the NBE peak in the PL spectra of n-MgZnO were both stronger than that of p-MgZnO. The reason was believed that the new defects were introduced by As diffusion.关键词：p-type MgxZn1-xO film;PL100|124|1更新时间：2020-08-11
- 摘要：Micrometer-sized spherical ZnO ultrafine powder was prepared by polyvinyl alcohol gel method. Zinc acetate was used as starting material,polar polymer polyvinyl alcohol with long chain was used as grids localization and lattice reagent to control nucleation and crystal growth via ionic complexation between the hydroxy groups and Zn2+ ions. The products were obtained by changing thermal treatment under controlling rise rate. The as-prepared ZnO powder was characterized by X-ray diffraction (XRD), scanning electron micro-scopy (SEM) and photoluminescence (PL) spectra. The analytical results of SEM and XRD indicate that the concentrations of the PVA solution, sintering temperature are the factors influencing the preparation. It is found that the uniform spherical ZnO with diameter about 1~3 μm are obtained under the conditions of a PVA concentration of 5% and sintering temperature of 500℃ at which most of polymer are removed after 3 h.The PL spectra of these samples include two blue emission peaks, centered at 407 nm which is attributed to the zinc vacancies and 468 nm which is due to the transition of electrons from the level of the ionized oxygen vacancies to the valence band at room temperature when excited with 325 nm light. The ultraviolet emission peak located at 385 nm which originates from the interband transition of electrons has been observed at certain temperature. It is found that the intensities of these peaks vary with annealing temperature. With increasing the heat treatment temperature, the blue emission peak at 407 nm gradually disappears. The intensities of ultraviolet emission peaks are sharply enhanced and approach a maximum value for the sample prepared at 500℃, then it decreases as the annealing temperature increase up to 600℃.关键词：polymer network gel method;PVA;spherical ZnO;PL spectra121|131|1更新时间：2020-08-11
- 摘要：ZnO films were grown on (0001) Al2O3 substrates by photo-assisted Metal Organic Chemical Vapor Deposition (PA-MOCVD). The effects of photo-assisted on the properties of ZnO films were studied by X-ray diffraction, transmission spectrum and Van der Pauw Hall effect, respectively. The results indicated that the samples prepared under photo irradiation have better crystal and optical quality, and they have lower electron concentration. The light irradiation during the growth of ZnO films is benefit for the decompositon of metal organic source, and can afford enough energy for these adsorption atoms migrating to proper lattice position.关键词：ZnO thin film;photo-assisted MOCVD;optical property127|278|2更新时间：2020-08-11
- 摘要：Dilute magnetic semiconductors(DMSs), such as MnGaAs, MnCdTe, CoZnO, and FeZnO, offer the great opportunity to integrate the magnetic, electrical, and optical advantages into a single semiconductor material. Therefore, DMSs attract more and more interests for the application in spintronics field. However, incorporation of transition metal ions will inevitably effects on the optical and electrical properties when the magnet functionalities are introduced into semiconductors. Besides the quenching behavior in fluorescence due to the complex energy level system, the effect of transition metal ions on conduction of the matrix is not neglectable because of the alterable valence. In present work, we found that doping of Fe ions changes the conduction type of the CdS thin films form n-to p-type. The Fe related donor-acceptor pairs emission was discussed by photoluminescence (PL) characterization. Cd1-xFexS thin films with different Fe contents were grown on c-plane sapphire substrate by low-pressure metal organic chemical vapor deposition. Dimethyl cadmium, iron pentacarbonyl and H2S were used as precursors, flow rates of which were fixed at 3.51×10-6, 3.77×10-7 and 1.62×10-5 mol/min by separate mass-flow controllers, respectively. High purity hydrogen (99.999%) was used as carrier gas with total flow rate of 1.9 liter/min. The growth was performed for 30 min, and the thickness of samples ranges from 500 to 700 nm. A Lake Shore 7707 Hall measurement system was employed to measure the electrical properties of the thin films. PL measurements were performed on a JY-630 micro-Raman spectrometer in a backscattering geometry configuration. The excitation source for the PL is the 325 nm line of a He-Cd laser. The Fe contents in samples A, B, C, D, and E are 0.0025, 0.0072, 0.0149, 0.0455, and 0.1400, respectively, which were measured by energy dispersion spectroscopy. The resistivity of the thin films was found to increase with the addition of more Fe contents into the Cd1-xFexS thin films, and eventually the conductivity of Cd1-xFexS thin film reverses from n-to p-type at high density Fe doping. Because the samples were Cd-rich, the acceptors can be only offered by Fe ions doped into the CdS films. The p-type conduction was attributed to the ionization of holes from trivalent Fe ions, which was formed by the oxidation of Fe2+ ion near the sample surface. With increasing Fe content, the band-to-band transition at 2.5 eV was suppressed while the emission located at 2.0~2.4 eV finally dominated the PL spectra. Under various excitation density, the PL emission located at 2.0~2.4 eV shows significant evolvement. The intensity of high-energy side of this emission increases more rapidly than that of the low-energy side with increasing excitation density. Therefore, the emission at 2.0~2.4 eV was attributed to donor-acceptor pairs. According to the PL peak position and carrier density obtained by electrical measurement, the energy level of Fe acceptor was calculated to be about 320 meV by using the formula.关键词：CdFeS;donor-acceptor pairs;energy level of acceptor99|186|1更新时间：2020-08-11
- 摘要：A Zn1-xFexO diluted magnetic semiconductor was synthesized with Sol-Gel method. Combining zinc acetate dehydrate with FeCl2 in a certain percentage and dissolve in ethanol, using lactic acid as stabilizer, transparent sol can be synthesized after three hours reaction. Powder sample can be formed through the process of drying by distillation, elimination of organics and heat processing. Crystal structure of Zn1-xFexO sample was analyzed with X-ray diffraction, and only ZnO diffraction peaks can be found with doping concentration lower than 6.66%. An increase in the hexagonal lattice parameters of ZnO is observed on increasing the Fe concentration. M-T curve of the powder material was measured with Superconducting Magnet System, the magnetic loop can be observed at the temperature of 10 K.关键词：sol-gel method;diluted magnetic semiconductor;ZnO116|103|2更新时间：2020-08-11
- 摘要：GaN is a very important semiconductor with a wide direct bandgap (3.39 eV), and has strong light emission in blue and UV regions. It has found extensive commercial applications in lasers and light-emitting diodes. Recently Si substrate is regarded as one of most promising substrates for GaN epitaxial growth due to its high quality, low cost, extensively existing in electronic industry and so on. However, it is very difficult to grow high quality GaN epitaxial layer due to great difference in lattice constant and thermal expansion coefficient.In our experiment, GaN film composed of crystalline microsheets was synthesized on Si(111) substrate by chemical vapor deposition, employing Ga2O3 and NH3 as Ga and N sources respectively. No buffer layer was used. The as-grown product was tested and characterized using SEM, EDS, XRD, TEM and PL. The results show that the as-grown product is a high quality GaN film which is composed of crystalline microsheets with less defects. The size of crystalline microsheets is hundreds of nanometers and the thickness in the range of tens of nanometers. GaN film integrates tightly with Si substrate, the surface of which is flat, compact and no cracks. A strong band-edge emission peak at 367 nm(3.378 eV) is observed. The growth mechanism is discussed briefly.关键词：GaN film;CVD;growth mechanism134|125|1更新时间：2020-08-11
- 摘要：We have investigated experimentally and theoretically the effect of quantum confinement on the acceptor binding energy in the GaAs/AlAs multiple-quantum well system, respectively. The system represents the maximum possible confinement for the acceptor states in the valence band and thus the maximum possible tuning range for the 1s-2p transition of the acceptor. A series of Be delta-doped GaAs/AlAs multiple quantum wells with the doping at the well center were grown on a semi-insulating (100) GaAs substrate by molecular beam epitaxy. The quantum-well width ranges from 3 to 20 nm. Each of multiple-quantum well structures investigated contained a same 5 nm wide AlAs barrier, while every GaAs well layer was delta doped at the well center with Be acceptor atoms. The doping level was 5×1010/cm2. The photoluminescence spectra were measured at 4, 20, 40, 80, 120, and 200 K, respectively using Renishaw Raman imaging microscope. The optical excitation for photoluminescence experiments was provided by an argonion laser 514.5 nm. The excitation power was typically 5 mW. The two-hole transitions of the acceptor-bound exciton from the ground state, to the even-parity excited state, have been clearly observed. The acceptor binding energy of the shallow beryllium acceptor at the center of the multiple-quantum wells has been measured experimentally. Under the single-band effective mass and envelop function approximation, a variational calculation is presented to obtain the acceptor binding energy as a function of quantum-well width. We choose the produce of two terms as the trial wave function of a hole. The Bohr radius is employed as a variational parameter in order to minimize the total energy of the system. The total energy of the system can be solved for any choice of the Bohr radius by expanding the derivatives in finite differences and forming an iterative shooting algorithm. It is found that the experimental results are in good agreement with the theory.关键词：effect of quantum confinement;delta-doped;GaAs/AlAs multiple quantum wells;photoluminescence spectra123|151|0更新时间：2020-08-11
- 摘要：Amorphous-Si:H/SiO2 multilayers with various sub-layer thicknesses were layer-by-layer deposited and in situ plasma oxidized in a plasma-enhanced chemical vapor deposition system. Nano-crystalline Si can be formed in the initial a-Si sub-layers based on the constrained crystallization principal. Raman scattering and TEM measurements were used to characterize the structure of multilayers during the formation of nc-Si/SiO2 multilayers. It was found that the annealing temperature and the a-Si:H sub-layer thickness influence on the crystallization process obviously. Photoluminescence was observed at room temperature and the PL peak position is about 750 nm. Light-emitting Diode with MOS (Metal-Oxide-Semiconductor) structure was designed and fabricated by evaporating Al electrodes on both the upper and the bottom surface of the sample. Electroluminescence at room temperature was also observed by the naked eye with the turn-on voltage of 6 V. The EL spectra contain two luminescence bands located at 520 nm and 650 nm, respectively. The influence of nc-Si and interface of nc-Si and SiO2 on the luminescent character of the device was briefly discussed.关键词：nc-Si;structure;photoluminescence;electroluminescence106|162|2更新时间：2020-08-11
- 摘要：The absorption and photoluminescence spectra of the CdSe/ZnS quantum dots dispersed in hexane and toluene solution are measured in different temperatures. Effect of the temperature on the absorption and photoluminescence spectra is discussed by comparing the spectral characteristics of two types of the CdSe/ZnS quantum dots. The measured results indicate that the absorption-peak wavelengths have a slight red shift (~4 nm) as the temperature increases, the photoluminescence-peak wavelengths having a little red shift, but no more than 6 nm as the temperature increases since 25℃ to 100℃. Two experiential coefficients in Varshni law regarding to bandgaps are determined at the first time according to the measured PL spectra of the CdSe/ZnS quantum dots. The measured abilities of the absorption show a little change with different temperatures, and photoluminescence intensities are proportional to the increase of the temperature.关键词：CdSe/ZnS quantum dots;solution temperature;absorption spectra;photoluminescence spectra174|278|7更新时间：2020-08-11
- 摘要：CdTe nanocrystals were synthesized in aqueous solution with thioglycolic acid (TGA), L-cysteine (L-Cys), 3-mercaptopropionic acid (MPA) and 1-thioglycerol (TG) as stabilizers. We systematically investigated the effect of different stabilizers on the optical properties of CdTe nanocrystals and the stability of spherical CdTe nanocrystals and nanorods. The results indicate that different shapes, absorption spectrum and PL emission spectrum of CdTe nanocrystals can be obtained with using different stabilizers contained TGA, MPA, TG and L-Cys. It is due to the influences of stereo-hindrance effect and functional groups of different stabilizers.关键词：CdTe;nanocrystals;stabilizers;optical properties109|81|4更新时间：2020-08-11
- 摘要：The photoluminescent properties of nanocrystalline ZrO2:Dy3+ powders were studied in this paper. We observed the room temperature sharp characteristic emission of Dy3+, its concentration quenching and the energy transfer between the nanocrystalline ZrO2 host and the rare earth ion Dy3+. The sintering temperatures gave appreciable influence on the crystalline phases of the nanocrystalline ZrO2. As the sintering temperature was changed, the crystalline phase was also changed, which made the characteristic emission of Dy3+ obvious different. It is shown that there exist two emission centers for the rare earth ion Dy3+ which occupy different crystalline phases produced by calcining samples at different temperatures. The studies on the effect of the doped Dy3+ concentration on the fluorescence emission intensity show that there exists the concentration quenching phenomena of the rare earth ion Dy3+in the nanocrystalline ZrO2 host. The optimum doped concentration depends on the crystalline phase of the host. Different crystalline phases cause different quenching concentration. The optimum concentration for the luminescence Dy3+ is determined to be 0.5% for the tetragonal structure and 1% for the mixture crystalline phases. The energy transfer process also depends on the crystalline phase of the host. The energy transfer efficiency is the most highest for the 950℃ sample. A model for microscopically explaining the energy transfer processes between the nanocrystalline ZrO2 host and Dy3+ was given.关键词：nanocrystalline ZrO2：Dy3+;photoluminescence;energy transfer;concentration quenching90|219|0更新时间：2020-08-11
- 摘要：ZnO self-assemble nano-crystals were synthesized from ZnO and graphite powder by carbon thermal reduction. The lattice phase, morphology and photoluminescence property of the sample were characterized using XRD, SEM and PL spectrum. The results show that the product is wurtzite ZnO hexagonal nanotubes with multiple layers. Room-temperature PL spectra show that ZnO hexagonal nanotubes exhibite broad green emission centered at 545 nm, and enhanced red emission.关键词：ZnO;tube structure;growth mechanism;photoluminescence121|169|2更新时间：2020-08-11
- 摘要：NaGdF4 nanocrystals were prepared using a polyol method and were characterized by powder X-ray diffraction (XRD) patterns, field emission scanning electron microscopy (FE-SEM) images and FTIR spectra. Down-conversion luminescence of NaGdF4:1%Eu3+ nanocrystals and up-conversion luminescence of NaGdF4:6%Yb3+,1%Er3+ nanocrystals were studied. Annealed samples were compared with unannealed samples. The X-ray diffraction results showed that the prepared samples were hexagonal phase of NaGdF4. Field emission scanning electronic microscopy revealed that the average diameter was 15, 18 and several hundreds nanometers for nanocrystals unannealed, annealed at 400℃ and annealed at 600℃ respectively. After being annealed at 400℃ for 2 h, 5D1-3/5D0 emission intensity ratio increased remarkably for NaGdF4:1%Eu3+ sample; up-conversion emission intensity increased at least by factor of 67 for NaGdF4:6%Yb3+,1%Er3+ sample. These increases were attributed to the anneal-derived decrease of OH- species etc. These species have high energy vibrations and can make multiphonon relaxation occur easier. The oxygen contamination is at very low level, undetectable by optical spectroscopy method in samples unannealed and annealed at 400℃, but is detectable by optical spectroscopy method in sample annealed at 600℃. Two-photon processes are involved in the green and red upconversion luminescence and three-photon are involved in the blue upconversion luminescence.关键词：NaGdF4;polyol method;up-conversion107|42|2更新时间：2020-08-11
- 摘要：NaYF4 nanoparticles doped with Yb3+,Tm3+ ions were synthesized by hydrothermal method. The upconversion emission spectra excited by 980 nm were measured. The developments of upconversion emission characters are studied on the synthesis temperature, the reaction time and Tm3+ concentration. The strongest blue emission is obtained under the excitation of 980 nm laser when synthesis temperature is 180℃, reaction time is 120 min, and Tm3+concentration is 0.04%.关键词：hydrothermal method;upconversion emission;NaYF4：Yb;Tm106|78|1更新时间：2020-08-11
- 摘要：Usually, CCFL is used as the back light sources for the traditional thin film transistor liquid crystal display. Now, among several light sources for LCD backlight, LED is the most competitive one. The paper analyses the performance of LED and designs a new LED for large area direct LCD backlight,which is simple and has a good performance. In order to test the LED designed by us, we design a 26′ LCD backlight finally. The simulation result indicates that the performance of the LED designed by us is good enough to meet the requirement of LCD backlight about luminance uniformity and color balance.关键词：LED;LCD backlight;large area backlight;direct backlight112|245|4更新时间：2020-08-11
- 摘要：A kind of spectral emissivity measuring apparatus has been developed, which can perform spectral emissivity measurement by means of comparing two symmetric beam paths. The apparatus can be used to measure the surface temperature of material by utilizing multispectral pyrometry, and the problem that irregular surface temperature of material is hard to be exactly measured was resolved. The surface emissivity and surface temperature measurements were realized synchronously.关键词：emissivity;pyrometry;multispectral pyrometry111|76|1更新时间：2020-08-11
- 摘要：Based on properties of the noise module on the CCD output signal, general methods to suppress different noise were introduced. Based on area array CCD, the technique of suppressing noise of CCD signal acquisition scheme was presented. Noise suppressing and processing circuits of CCD signal acquisition scheme were designed. These circuits were used in signal acquisition scheme of CCD442A.The SNR of the acquisition system was also calculated by means of integrating spheres. According to the simulation and laboratory radiometric calibration experiment, the results show that the reset noise and the dark current noise are suppressed by the signal acquisition scheme of CCD442A with correlated double sampling(CDS) and black level offset compensation, and the system SNR exceeded 40 dB at medium illumination.关键词：area array CCD;reset noise;dark current noise;correlated double sampling (CDS);black level offset compensation103|77|9更新时间：2020-08-11
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