最新刊期
卷 7 ， 期 4 ， 1986
- 摘要：The integral and differential equations of the polarization eigenmodes in dielectric bilayer systems were straightforwardly deduced by means of macroscopic electric potential caused by the surface and bulk polarization charges. It is shown that the polarization eigenmodes should be normalized according to (18) described in the text. The operator representations for the Hamiltonian of the polarization eigenmodes and the interaction between the charged particles and the polarizable media were also deduced which are, respectively, given in (24) and (28).In the section IV,we assume that the dielectric media are filled in the half-space of x3>0 and x3<0, respectively, and are in contact at x3=0. It is shown that there are three kinds of phonons coiresponding to the p-polarized wave. They are surface longitudinal optical (SO), surfacen transverse optical (TO) and longitudinal optical (LO) phonons. The interaction of the charged particles with p-polarized SO phonons is equivalent to SO phonons with an effective frequency of ωeff,±SO and can be described by introducing a Frölich-like coupling constant α±SO The interaction of the charged particles with LO phonons is, in essence, that with the bulk LO phonons, but is weakened by the surface effects.97|104|0更新时间：2020-08-11
- 摘要：In this paper, the "three-parameters theory" model (TPM) is applied to two groups of compounds with a scheelite structure: Na5Eu(MO4)4 and its variation: Gd2(MO4)3 (M=Mo, W).The set of a priori crystal field parameters (CFPs) obtained for the double salts having a S4 point symmetry (which is treated as D2d), is used for Gd2(MO4)3:Eu3+. The scheelite subcells can be found in the later structure although the symmetry is lowered to monochinic, with C1 as the site symmetry.101|37|0更新时间：2020-08-11
- 摘要：High-purity single crystals of ZnSxSe1-x (x=0.15) were grown with sublimation method under a controlled partial pressure of selenium and sulphur corresponding to the minimum total pressure. The crystal wafers were taken from the grown ZnSxSe1-x single crystal on cleaving along the (110) cleavage plane. The cleaved crystals were heat-treated at 1024℃ for 64 hours in molten Zn, which is labelled sample A. The sample A was heat-treated again at 350℃ for 3 hours, this sample is labelled B. When the sample A was heat-treated at 1030℃ for 119 hours under 100 Torr of the zinc partial pressure, it is labelled C. Ohmic contacts of In dot were made with a supersonic soldering iron. The carrier concentration and Hall mobility of n-ZnSxSe1-x(x=0.15) were measured at the range of from liquid nitrogen temperature to room temperature with Van der Pauw method.99|37|0更新时间：2020-08-11
- 摘要：Blue electroluminescence of ZnSe MIS diodes had been obtained in the near band edge emission region[1,2] and the stimulated emission had also been observed in this region[3,4]. Many work in the origin of the blue emission of ZnSe at room temperature (RT) had been reported. The blue emission of ZnSe at RT was contributed by free exciton emission[5], the overlapping between free exciton emission and band-to-band transition[6], the emission due to the excitons which bounded to neutral donors[7], the band-to-band radiative recombinations[8], the bound-to-free transitions[9], and the exciton-carrier interaction[10,1].In our earlier work, attention was focused on the identification of the free exciton emission[11] and the determination of the origin of the blue emission band[1] in ZnSe crystals. In this paper the recombination process of the blue emission at RT from VPE ZnSe epilayers was studied. It was found that the origin of the blue emission at RT could be contributed by the exciton-carrier interactions.95|44|0更新时间：2020-08-11
- 摘要：The n-type InGaAsp cathodeluminescence spectra at 77K was studied. Using the model of the transition from conduction band to like-acceptor levels, we calculated the dependence of the Moss-Burstein shift on the doping concentration and the cathodeluminescence of heavy doping InGaAsp. The effect of the band tail of heavy doping samples was taken into account in the calculation. The theoretical values are consistent with the experimental ones.115|45|0更新时间：2020-08-11
- 摘要：ZnSe is one of the promising materials in application to blue light emitting diodes because of its wide direct band gap. Many papers on MIS[1,2] and p-n[3] structure blue EL devices of ZnSe bulk single crystal have been reported. Recently, low temperature growth techniques such as MOCVD[4], MBE[5]and VPE[6,7]are of particular interest. Usually these undoped ZnSe epilayers are of low resistivity. The conductivity in undoped ZnSe epilayers may originate from native donors[8,9] or extrinsic donor impurities[10,11].In this paper, it is reported that the photoluminescence and electrical properties of ZnSe epilayers grown on (100)-GaAs are influenced by the purity of source materials, and suggested that the conductivity in normally undoped VPE ZnSe was attributed to the extrinsic donor impurities which originated in the contamination of the ZnSe source materials rather than in the native donors or Ga outdiffused from the substrate of GaAs when the growth temperature is low (Tsub=500℃).106|55|0更新时间：2020-08-11
- 摘要：The systems of CeMgAl11O19-SrAl12O19 and CeMgAl12O19-SrMgAl10O17 were studied. In CeMgAl12O19-SrAl12O19, complete solid solutions were observed and the positions of the lower d-band edge and emission peak of Ce3+ shifted to higher energy while the cell of the solid solutions contracted as a result of decrease of the parameter a as the concentration of SrAl12O19 increased. Furthermore, both the Nephelauxetic effect and the crystal field intensity of Ce3+ decreased with increasing SrAl12O19 concentration. Except for 0.9 CeMgAl12O19-0.1 SrAl12O19, the emission position of Ce3+ in energy increased linearly with increasing SrAl12O19 content, which could be accounted for by power development fashion of the relation E=Q [1-(z/4)l/z 10-ar] (see ref. [6]). For 0.1 CeMgAl12O19-0.9 SrAl12O19,the deviation of the emission peak of Ce3+ from the straight line position could be due to a small Stokes shift for the compound. For CeMgAl12O19-SrMgAl10O17, solid solutions were observed only when SrMgAl10O17 content was within 70%.In the solid solutions,the emission peak energy of Ce3+ increased linearly,and the cell parameters a and c decreased and increased respectively with increasing SrMgAl10O17 concentration. For 0.1 CeMgAl12O19-0.9 SrMgAl10O17, two phases were found with SrMgAl10O17 as the primary phase and a magnetoplumbite-type Ce-and Si-double hexaluminate as the second phase, The emission of Ce3+ in the mixed phases originated probably from the latter compound.The intensity of Ce3+ emission in solid solutions was considerably enhanced by adding H3BO3 to starting materials. But the Ce3+ emission would reversely decrease if the quantity of H3BO3 was too high. It was found that the change of crystal habit of solid solutions by H3BO3 and the substitution of B for Al in the compounds were responsible for the observations.94|20|0更新时间：2020-08-11
- 摘要：Epitaxial growth of GaN has been investigated by a large number of people. However, few publications relate to the pattern of the formation of pits and hills on the surface of GaN epitaxial layers during the growth process. Some authors have given an explanation based on the growth mechanism of GaAsP. They believe that the formation of pits or hills on the surface of GaN epitaxial layers probably depends on the amount of GaCl in the growing zone. If GaCl in the growing zone is not enough, pits will occur. On the contrary, hills will be caused. We have investigated the effect of conversion rate of HC1 and Ga on the morphology of GaN. Our experimental results are contradictory to the reference as mentioned above. A tentative explanation is given in this paper.107|61|0更新时间：2020-08-11
- 摘要：This paper describes the thermal oxidation of GaAs carried out in a closed tube. During the oxidation process, a GaAs wafer to be oxidized was placed near one end of the quartz tube at the temperature of 525℃ and high purity powder of As2O3 was put in a platinum bcat near the other end of the tube at 460℃. A wafer of Te-doped n-type GaAs (100) with a carrier concentration of 5×1018cm-3 was used in the experiments. The chemical and electrical properties of the native oxide films were studied. The varactor diode was fabricated in standered planar process with the native oxide films mask against impurity.In the study, in-depth profiles of the native oxide films were measured by means of AES combined with sputter etching by argon ions. AES and XPS measurements were carried with a PHL Model 550 electron spectrometer.106|63|0更新时间：2020-08-11
- 摘要：This paper describes the growth mechanism and the characteristics of ZnSe epilayers by Metal-Organic Chemical Vapour Deposition (MOCVD) at atmospheric pressure. Gas flow patterns, entrance effects and boundary layers within reactors have been investigated.The experimental techniques employed are TiO2 smoke trace and it’s photogrammetry. The results are analysed in terms of accepted simplified theories of gas flow dynamics involving a group of dimensionless number-Re, Ra and Gr/Re2. The de-pendance of the stagnant layer thickness (δ) on the distance along substrate holder (x), the gas velocity (U∞) and the temperature (T) was experimentally observed.It tallys with the Berkman’s typical expression for the boundary layer thickness.The growth rate (G) has been studied as a function of distance along (x) and across (z) the susceptor. It is independent of the temperature between 450-530℃ for Diethylzinc (DEZ)and 280-390℃ for Dimethylzinc (DMZ) respectively. This shows that the deposition is controlled by the diffusion of reactants across the stagnant layer.91|63|0更新时间：2020-08-11
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