摘要:

Electrochromism was newly realized in a WO3–Pb(Zr0.52Ti0.48)O3(PZT) system which utilized the piezoelectric property of PZT ceramics for power supply. The electric power produced by Mn-doped PZT ceramics enabled the WO3film to color blue. High piezoelectricity with a peak voltage of 35 V and peak current of 1.2 mA on a 30 k&OHgr; circuit was observed at a pressure of 30 MPa for the present system. This study shows the possibility to actuate the electrochromic WO3film with PZT ceramics. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118654

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Unusually fast mutually pumped phase-conjugation (MPPC) is achieved in aBi12TiO20crystal by using transient photorefractive beam coupling under a dc electric field. Pulses of phase-conjugate waves with a buildup time of 4.5 ms and a width of 50 ms at an input intensity of 2×0.8W/cm2are obtained after applying a rising front of external electric field to the crystal. A phase-conjugation efficiency as high as 25&percent; of the incident light power is measured. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118656

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Photoluminescent and electroluminescent studies of bilayer heterojunctions formed from a poly(pyridyl vinylene phenylene vinylene) (PPyVPV) derivative and poly(vinyl carbazole) (PVK) show an emission peak which cannot be ascribed to either the PPyVPV derivative or PVK layer. Through studies of absorption and photoluminescence excitation (PLE) spectra we demonstrate that the additional feature results from an exciplex at the bilayer interface. The photoluminescence efficiency of the exciplex is greater than 20&percent;. The electroluminescence spectrum from the bilayer devices is entirely due to exciplex emission, with internal efficiencies initially achieved exceeding 0.1&percent;. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118657

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Violet/blue photoluminescence was observed from epitaxial cerium oxide films on silicon substrates. The films were deposited on silicon (111) substrates under ultrahigh vacuum conditions using pulsed laser ablation of a cerium oxide target and treated by rapid thermal annealing in argon. High resolution transmission electron microscopy and x-ray diffraction measurements indicated the formation of a single crystal cerium oxide phaseCe6O11different fromCeO2in the annealed films. The emission might be due to charge transfer transitions from the4fband to the valence band of the oxide. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118658

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We report a comparison between measured and calculated far field data for an optically pumpedIn0.15Ga0.85N/In0.05Ga0.95Nmultiquantum well laser structure with AlGaN cladding layers. Optical pumping of the semiconductor device was performed with a pulsed 337 nmN2laser, whose beam was focused to a narrow stripe. A thin upper cladding layer allowed efficient pumping of theIn0.15Ga0.85N/In0.05Ga0.95Nlaser structure. Despite high distributed cavity losses of at least30 cm−1,and although gain occurred in the small active region only, the seventh order transverse mode was supported in a waveguide formed by the entire 5-&mgr;m-thick epitaxial layer structure. Excellent agreement is demonstrated between measured and calculated far field patterns of the lasing mode. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118659

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

X-ray generation enhancement from a laser-produced plasma with a porous Si target is reported. For a porous surface formed on a Si wafer, the self-reflectivity of a femtosecond pulse becomes considerably small. The observed energy penetration depth is 25–30&mgr;m, which is much larger than the skin depth of solid density matter. Using a porous Si target, the threshold of the pre-pulse intensity required for soft x-ray emission enhancement can be reduced. It also contributes to enhance the pre-pulse effect, and soft x-ray generation enhancement ranging from 1.6 to 6.5 times is observed depending on the pre-pulse intensity. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118660

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Characteristic rate variations of carrier processes are imaged using near-field scanning optical microscopy. We couple both a visible pump and an infrared probe light through a subwavelength aperture to investigate the interband recombination and intraband diffusion of excess carriers in oxidized silicon. Typical values of the locally measured life time constants agree well with those obtained by conventional space-averaged techniques. Moreover, the images locate defects, reveal variations, and can map the regions in which a recombination process is active. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118661

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We have detected stimulated far-infrared emission from copper-doped germanium single crystals. By varying the magnetic field between 1 and 2.3 T, we have achieved emission in the range of 70–120cm−1.Laser action was observed for crystals with a copper acceptor concentration as high as1.5×1015cm−3,a doping level that is considerably higher than that of any single or double acceptor doped Ge laser. Stimulated emission from Ge crystals with such a high Cu concentration is possible because only a small fraction of the copper acceptors is ionized during operation. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118662

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Reflectance modulation measurements have been used to determine facet temperatures of InGaAs/GaAs double quantum well (QW) graded-index separate-confinement heterostructure ridge-waveguide lasers possessing band gap tuned passive cavity sections. We find that the incorporation of transparent extended cavities, produced by ion-implantation enhanced QW intermixing, significantly decreases the laser facet temperatures. The reduced photoabsorption occurring at the facets, achieved by the QW intermixing process, should lead to increases in both the maximum optical power levels and device longevity prior to the onset of catastrophic failure. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118663

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Remarkable improvement in stability has been demonstrated in an organic electroluminescent (EL) device using a doped emitter consisting of 8-hydroxyquinoline aluminum (Alq) as the host and N,N-dimethylquinacridone (DMQA) as the emissive dopant. A luminance half-life on the order of about 7500 h has been achieved in the DMQA/Alq EL device, operating under a constant current of 20mA/cm2and starting at a high luminance of 1400cd/m2.The improved stability was attributed to the elimination of intermolecular hydrogen bonding between the dopant molecules. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118664

出版商:AIP    

年代:1997

数据来源: AIP