摘要:

The temporal behavior of the electroluminescence (EL) from thin-film indium-tin-oxide (ITO)/aromatic diamine (TPD)/Al(III) 8-hydroxyquinoline(Alq3)/Mg/Aglight-emitting diodes (LEDs) upon the application of a rectangular driving voltage is analyzed in terms of the electron-hole recombination on theTPD/Alq3interface. From the long-time component of the temporal decay of the EL intensity the electron-hole recombination coefficient&ggr;=(1.1±0.5)×10−10 cm3/sis determined in good agreement with the value expected on the basis of the Langevin theory of recombination with the recombination process controlled by the motion of holes in the hole-transporting TPD layer of the LED. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120805

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

This analysis is made of the spectral dependences of the position of the fundamental absorption edge, the photoconductivity, and the optical spectra ofCdxHg1−xTe(0.35<x<0.40)alloys at temperatures 5–300 K in the wave number region(30–5000) cm−1.The nonmonotonic dependence on temperature of the parameters considered is investigated. The reflection spectra are analyzed mathematically by means of dispersion analysis and the Kramers–Kroning relations. The results obtained are explained by the influence of polaron effects on the processes of charge transport in the crystal. It is conjectured that the polaron configuration changes at the characteristic temperatures 60, 160, and 225 K. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120806

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Ink-jet printing was used to directly deposit patterned luminescent doped-polymer films. The luminescence of polyvinylcarbazol (PVK) films, with dyes of coumarin 6 (C6), coumarin 47 (C47), and nile red was similar to that of films of the same composition deposited by spin coating. Light emitting diodes with low turn-on voltages were also fabricated in PVK doped with C6 deposited by ink-jet printing. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120807

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

The emission of electrons from a prepoled ferroelectric material when shined with a laser light pulse cannot be interpreted as a normal photoemission process, nor due to polarization switching. Another picture is proposed for the emission: in a prepoled ferroelectric disk a very narrow layer of electrons is set at the surface. The high-power laser pulse is absorbed by the electrons and an Auger process occurs. Hence, part of the hot electrons acquire enough energy to tunnel and/or to overcome the potential barrier and exit the crystal. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120808

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

A new phosphor,(Gd1.54Zn0.46)O3−&dgr;:Eu0.063+,with a photoluminescent quantum efficiency of≈86&percent;and a superior color chromaticity (x=0.656,y=0.344) compared to the state of art red phosphorY2O3:Eu3+was identified using the combinatorial thin film synthesis method. This phosphor may replaceY2O3:Eu3+in display applications where a more saturated red phosphor is preferred. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120809

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Alterable temperature-dependent emission wavelength shifts were observed from(InP)2/(GaP)2short-period superlattices (SPSs) quantum wells grown with different interruption periods. Photoluminescence spectra showed that the peak energy of the SPS samples is inversely proportional to the interruption time conducted between the two consecutive binary growth sequences in the SPS regions. It is believed that a lateral composition modulation occurred during the interruption period which resulted in periodic In-rich and Ga-rich regions in the SPS quantum wells along the growth plane. With the lateral compositional variation, temperature variation can induce a multiaxial strain effect which can either amplify or reduce the temperature-dependent wavelength shift of the SPS quantum wells with different interruption periods. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120810

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

This letter reports continuous wave laser emission at 524 nm from a self-frequency-doubled infrared laser ofLaBGeO5:Nd3+operating at a fundamental wavelength of 1048 nm. Resonant pumping in the spectral region around 800 nm for laser diode pumping is investigated and optical losses are estimated. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120811

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

We have observed an anomalously large blueshift of the apparent donor–acceptor pair transition peak as the laser intensity increases in compensation-doped coupled quantum wells. The mechanism for the blueshift is the change of the Coulomb interaction energy between the recombined donors and acceptors due to the decrease in their separation as the laser intensity increases. The blueshift is accompanied by the saturation of the relative donor–acceptor pair transition peak intensity due to filling of the impurity states. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120812

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Results of room-temperature experiments with a multiple-quantum-well, nonlinear, contradirectional coupler are reported. A power-dependent, contradirectional coupling condition is demonstrated, inducing an optically controlled switching of optical signals, with a switching energy of 1 pJ. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120750

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

A side-chain nonlinear optical polymer consisting of copolymers of 4-methylamino-4′-nitrostilbene and methacrylate was poled and shown to be orientationally stable for almost 8 yrs. At approximately 110 °C below its glass transition, its electrooptic coefficient was reduced by less than 25&percent; of its initial value. In addition, adding an annealing step during the poling process further improved its orientational stability. These behaviors are consistent with existing empirical models describing poling relaxation of nonlinear optical polymers, and demonstrate that with appropriate molecular design, they can become viable nonlinear optical materials for commercial devices. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120751

出版商:AIP    

年代:1998

数据来源: AIP