最新刊期
卷 9 ， 期 1 ， 1988
- 摘要：Characteristic luminescence of rare earth(RE)ions have been demonstrated from RE doped Ⅲ-Ⅴ compound semiconductors,such as Yb,Er and Nd doped GaAs,InP and GaP.Because of the effective screen of suriounded 5S2 and 5P6 shells,the spectra of RE ions in Ⅲ-Ⅴ compound semiconductors exhibit narrow lines arising from intra 4f-shell spin-orbit levels transitions as in other solid state materials.Usually,the RE ion occupied cation sites of Ⅲ-Ⅴ semiconductors in different doping technologies.These RE-doped Ⅲ-Ⅴ semiconductors have exhibited promising applications for d-c pumped optoelectronic devices.This paper reviews recent research work on photoluminescence(PL)and electroluminescence(EL)chaiacteristics of rare earth doped Ⅲ-Ⅴcompound semiconductors.165|91|0更新时间：2020-08-11
- 摘要：In this paper,we extend the theoretic consideration of the electron-phonon inteiaction for a dielectric bilayer system to polar superlattice consisting of two alternately arranged different dielectric layers,assuming that the long wave approximation of the lattice vibration is still suitable for the superlattice.The integral equation characterizing the polarization eigenmodes of the superlattice is derived,as given by(2-3)-(2-5)in the text.One can see from this result that the superlattice can be regarded as an equivelent bilayer system with different boundary condition from simple bilayer.It is also verified that the differential equation satisfied by the polatization vector for the supsrlattice is as the same as for the real bilayer.The dispersion relation is derived from the boundary conditions suited for superlattice,which is given by(4-8).In this expression,a and b are the thickness of each layer,d=a+b,is the periodic length of the superlattice.When N,the number of periodic layers of superlattice,approaches infinity,i.e.N→∞,the dispersion relation is reduced to(4-9).It is droved from calculation that as long as N is larger than 20,such a supeilat-tice can be regarded as one with infinite layer number.If N=0,a→∞ and b→∞,the dispersion relation(4-8)is reduced to(4-11).When a→∞,the dispersion relation(4-8)is reduced to(4-12),and this is just the case of single qauntum well.The interaction Hamiltonian of the charged particle with SO phonon is obtaind,as given by(3-7),(4-15)and(4-16).Because the charged particle interacts only with the LO phonon of the dielectric layer in which the charged particle is located,the interaction Hamiltonian of the charged particle with LO phonons for superlattice is as the same as for the bilayer.We also extend the above discussion to the semi-infinite superlattice.We assume that the semiinfinite superlattice occupying the space oi z>0,and the space of z<0 is vacuum or the third media with dielectric function ε3(ω).In this case,the dispersion relation is derived,as given by(5-12).In addition,the interaction Hamiltonain oi the charged particle with SO and LO phonon is completely as the same as for the infinite superlattice.105|111|0更新时间：2020-08-11
- 摘要：Recently,much work on near band edge emission under high excitation density has been reported in ZnSe to obtain blue spontaneous and stimulated amission.But most of the researchs are concentrated on photoluminescence(PL).Saito et al.observed E and P bands in ZnSe in PL,which they attributed to exciton-electron(Ex-e)and exciton-exciton(Ex-Ex)interaction,respectively.Baltramiejunas et al.found that the effective exciton temperature used in ZnSe in PL was 79-150K,higher than the lattice temperature used(77K).Catalano et al.and Colak et al.reported the stimulated emission in ZnSe excited by photon and electron beam respectively.In our earlier work attention was focused on the identification of free exciton emission in forward-biased ZnSe MIS diodes under low excitation density,and proved that the effective exciton temperature was close to the lattice temperature.As far as we are aware that there is no reports on free exciton emission in forward-biased ZnSe MIS diodes with high pulse current density.91|53|0更新时间：2020-08-11
- 摘要：Al element is inportant donor impurity in ZnSe,which substitutes Zn site as a single donor with the level close to the conduction band.Meanwhile,AlZn may also combine with VZn to foim self-activated center(VZn-AlZn).Many authors have discussed the luminescence properties of Al-doped ZnSe at high temperature and veiy few have discussed it at lower temperature.In order to study behavior of Al inpurity in ZnSe,Al was doped into high-purity ZnSe single crystal by thermo-dirfusion technique under Zn saturation vapour pressure in the range oi 300℃-900℃.The photoluminescence spectra at liquid ni-quid nitrogen temperature show that very strong blue emission peaks in band edge and a broad emission band B located at 2.0eV were observed for undoped ZnSe;another band A,besides band B,was found at 2.3eV in Al-doped ZnSe.When the diffusion temperature is below 600℃,the emission intensities of Band A and B increase when the diffusion temperature increases and moreover,increasing rate of the emission in intensity for band B is more rapid than that of band A.Emission intensities of band A and B dropped down suddenly when the diffusion temperature over 600℃ For higher diffusion tempera-ture,their intensities increase again the increase of band B is slower than band A.132|68|0更新时间：2020-08-11
- 摘要：DCEL has been playing an important role in displays.At present,the main problem is maintenance.According to the deterioration model of Cu+ migration reported by most previous papers.The characteristics of CuxS can be improved by reducing deterioration.We report a new copper-coating technique used to produce the DCEL phosphors with special CuxS characteristics.99|50|0更新时间：2020-08-11
- 摘要：We present and discuss the experimental observation in which the peak position of the plasmon absorption band can be varied in a relatively wide spectral range,in fluo-roborates glasses containing dispersed silver particles,as a function of cerium oxide concentration.109|40|0更新时间：2020-08-11
- 摘要：In this work we investigated the 5D1-5D0 relaxation properties of Eu3+ in the La-phosphate glass.The composition of the sample has been given in reference,in which the iluorescent spectra and selective site spectra of the 5D0 state were investigated.The Fig.1 given the transmisson spectrum of the sample measured by Peken-Elmer spectrometer at room temperature.From Fig.l,it can be seen that 5D1 state is split into two stark levels,which crresponding to absorption peaks at 532 and 525nm.The former just overlap with the doubling frequency of YAG laser.Then the doubling frequency YAG laser was used as an excitation source,which have duration about 20 ns and wavelength at λ=532nm.The experimental apparatus of time-resolved spectra are shown in Fig.2.104|34|0更新时间：2020-08-11
- 摘要：This paper investigates the interaction between Sm3+ ions from both of dynamic and static aspects.On the basis of Hirayama theory,the donor relaxation in energy transfer for multipolar interaction can be expressed as:Φ(t)=Φ(0)exp[-t/τ0-(4/3)πГ(1-3/s)NAR03(t/τ0)3/s](1)where τ0 is the intrinsic decay time without acceptor,NA is acceptor concentration,R0 is the critical transier distance and s=6,8,10 ior EDD,EDQ,EQQ inteiaction respectively.113|68|0更新时间：2020-08-11
- 摘要：Energy transfer in binary polystyrene scintillators has been investigated by means of selection solute of several fluorescence behaviour.Excitation and fluorescent spectra,lluorescent intensity excited by γ,X and violet ray and relationship between the intensity and the solute concentration were measured.The dependence ol decay time of the solute fluorescence of polystyrene and the solute absorption peak on the solute concentration was also investigated.Energy transfer mechanism was discussed.108|59|0更新时间：2020-08-11
- 摘要：The fluorescence lifetime is an important characteristic of fluorescence spectroscopy.The measurement of lifetime can be used in a number of ways to obtain dynamic and structural information about molecules.But for the lifetimes in the magnitude of nanoseconds a high technique is required to measure them.Although there have been a large number of reports in the literature on the fluorescence spectra of polynuclear aromatic hydrocarbons(PAH),but the lifetime data of these molecules are not so abundant and in many cases the published values are in poor agreement with each other.For example,for fluoranthene,D.J.Ehrlich et al obtained 24 ns for 220℃ vapor and 22 ns for the cyclohexane solution by exciting the molecule at 351 nm,while L.J.Jan-dris et al obtained 38 ns for 60-95℃ vapor by exciting at 337 nm.This discrepancy is considered to be abnormal and repeated investigations are recommended.Using the presently most precise time-correlated single photon counting technique,we have measured eight PAHs which are important in fluorescence spectroscopy and in biochemistry.All solutions were bubbled with high purity nitrogen before the measurement.The excitation wavelength was 337 nm for all compounds and additionally 351 nm was also used for fluoranthene to verify the discrepancy between the values of both groups of authors.Our experiment gave out 39 ns for excitation at 337 nm and 36 ns for excitation at 351 nm,showing that there should be no essential dilference between the two cases.The lifetimes measured for other PAHs are either in agreement with literature value or are reasonable.93|43|0更新时间：2020-08-11
- 摘要：The fluorescence lifeime of a number of porphyrin free bases and metal-loporphyrins has been measured on a single photon counting apparatus.The HPD bulfer solution used as the sensitizer for the photodynamic therapy of cancer displayed a double exponential decay,with a short lifetime component of τ
3ns characteristic of aggregated HPD and a long liietime component of τ 14ns characteristic of the monomeric HPD;at the mean while,the HP buffer solution displayed a single exponential decay.The lifetimes of seven porphyrins or their metal complexes were measured for the first time.The measured lifetime of several substances are in good agreement with the calculated values. 123|63|0更新时间：2020-08-11 - 摘要：This paper describes the tuning principle and the experimental technique of OPO.Temperature tuning curves of LiNbO3 crystal OPO are calculated,and the experimental results of singly-resonant parametric LiNbO3 are shown.The tuning range of the signal wavelength was measured to be 1.3-2.0μm.The output energy at 1.9μm was 0.37mJ/pulse at 10pps.The device is a temperature tuned singly-resonant LiNbO3 OPO pumped by a Q-Switched 1.06μm Nd:YAG laser.The parametric oscillator cavity mirrors are designed for the transmittivity T≥90% at 1.06μm,and the reflectivity R≥97% at 1.3-2.0μm.The LiNbO3 crystal,with a length of and the phase matching angle 6 of 50°,was coated with an anti-reflective layer(T≥80% at 1.06-2.0μm).The crystal was mounted in the oven with the temperature controlling accuracy of ±0.05℃.The tuning range of the signal wavelength was measured to be 1.3-2.0μm and the corresponding temperature range of the LiNbO3 crystal was 130°-250℃,The output energy at l,9μm was 0.37 mJ/pulse at 10pps,113|65|0更新时间：2020-08-11
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