摘要:

We have succeeded in fabricating a novel thin‐film electroluminescent device with a luminescent hole transport layer as an emitter. The cell structure is composed of an indium‐tin‐oxide substrate, a luminescent hole transport layer (emitter), an electron transport layer, and a MgAg electrode. The most essential feature of our device owes for adoption of an oxadiazole derivative as an electron transport layer. The emission intensity of 1000 cd/m2was achieved at a current of 100 mA/cm2.

ISSN:0003-6951    

DOI:10.1063/1.101586

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

A high‐power low‐threshold graded‐index separate confinement heterostructure AlGaAs single quantum well laser on Si substrates has been demonstrated for the first time by a hybrid growth of migration‐enhanced molecular beam epitaxy followed by metalorganic vapor phase epitaxy. The quantum well laser showed an output power of more than 400 mW per facet under pulsed conditions. A room‐temperature threshold current of 300 mA was obtained with a differential quantum efficiency of 40% without facet coating. The threshold current density was 550 A/cm2for a cavity length of 500 &mgr;m. These results show the highest peak power reported to date for low‐threshold lasers on Si substrates. The full width at half maximum of the far‐field pattern parallel to the junction was 6°. Threshold current densities as low as 250 A/cm2were obtained for lasers on GaAs substrates.

ISSN:0003-6951    

DOI:10.1063/1.101587

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We demonstrate the use of diluted multiple quantum wells to achieve low‐loss fiber‐matched optical waveguides. A fiber mismatch loss of 0.2 dB/interface and propagation loss of 0.4 dB/cm are achieved at 1.54 &mgr;m wavelength using InGaAsP/InP materials.

ISSN:0003-6951    

DOI:10.1063/1.101588

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

General Dynamics is investigating the Dielectric Cherenkov Maser as a rugged, compact, and tunable high‐power microwave source. This letter reports the test results of anS‐band device operating at 3.8 GHz. The device consisted of a dielectric (&egr;=10) lined cylindrical waveguide with waveguide radius 3.63 cm, and liner thickness 0.60 cm; and an annular electron beam with radius 2.54 cm. The beam parameters were 700 keV, 12 kA, 100 ns and yielded an rf pulse of 200 MW for 20 ns. A 15 kG axial guide field was used. The measured results agree with the numerical solution of the dispersion relation which includes the effect of the beam and liner.

ISSN:0003-6951    

DOI:10.1063/1.101589

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The performance of a series of InxGa1−xAs/AlGaAs (x=0.20 and 0.25) strained single quantum well (SSQW) lasers with lasing wavelengths in the range 930≤&lgr;≤1000 nm is discussed. Less‐strained devices, withx=0.20 and QW thickness 7 nm (&lgr;∼930 nm), perform comparably with GaAs QW lasers. Longer wavelength (&lgr;>950 nm), more highly strained lasers exhibit poorer performance. Our results suggest that interfacial recombination limits the performance at the longer wavelength structures.

ISSN:0003-6951    

DOI:10.1063/1.101590

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Experimental study of the change &dgr;&agr; in the absorption spectrum due to a static electric field is reported for very small CdSSe crystallites. We observe oscillations of &dgr;&agr; as a function of the wavelength, which are well explained as a Stark effect for the quantized electronic levels. A perturbation calculation is performed, which gives good theoretical fits of the experimental curves.

ISSN:0003-6951    

DOI:10.1063/1.102257

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

A resonant photoacoustic cell suitable for studies of liquid samples having low vapor pressures has been developed and tested. The cell, the working of which is based on that of the heat pipe, is of a simple, compact design; its operational temperature range is limited only by the choice of working fluid and the material used to construct the cell. The feasibility of this novel‐type cell has been demonstrated by obtaining the absorption spectrum of geraniol C10H18O at 403 K in the spectral region covered by the CO2laser emission.

ISSN:0003-6951    

DOI:10.1063/1.102302

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The formation of an amorphous phase between Co thin films and GaAs substrates by solid‐state reaction has been investigated by transmission electron microscopy and Auger electron spectroscopy. The amorphization is ascribed to the fast diffusion of Co in GaAs. The amorphous layer, after a 300 °C, 4.5 h annealing, is measured to be ∼40 nm in thickness and has a broad composition range. Prolonged annealing at 300 °C or heat treatment at 340 °C results in the crystallization of the amorphous phase. This crystallization is found to initiate from the Co/amorphous phase interface and leads to the formation of a metastable, supersaturated phase. Finally, the equilibrium condition is reached by the decomposition of this intermediate phase into CoGa and CoAs.

ISSN:0003-6951    

DOI:10.1063/1.101591

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We report an x‐ray diffraction study of a HgTe‐CdTe superlattice (SL)/HgCdTe heterostructure grown by molecular beam epitaxy (MBE). The diffraction results are used to place an upper bound on the misfit accommodation at the lattice‐mismatched SL/HgCdTe interface. The misfit accommodation at the heterointerface is at least an order of magnitude less than that predicted by equilibrium misfit theory. It appears that the low substrate temperature used in MBE HgCdTe growth imposes a kinetic barrier to misfit accommodation.

ISSN:0003-6951    

DOI:10.1063/1.101592

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Amorphous Si layers prepared by MeV Si implantation of (100) wafers have been studied by scanning and isothermal calorimetry. A homogeneous heat release of 5.1±1.2 kJ/mole and an interfacial heat release, due to crystallization, of 13.4±0.7 kJ/mole have been measured. Isothermal measurements unambiguously demonstrate the occurrence of the homogeneous release. The heat released isothermally at each temperature is between 6% and 8.5% of the total homogeneous release, and the time constants are only very weakly temperature dependent.

ISSN:0003-6951    

DOI:10.1063/1.101593

出版商:AIP    

年代:1989

数据来源: AIP