摘要:

The anomalous high absorption predicted to occur for an optical beam incident on a thin multilayered configuration having only slight intrinsic losses has been verified by means of a microwave model. This observation is consistent with a leaky‐wave interpretation for the reflection properties of the absorbing layered structure.

ISSN:0003-6951    

DOI:10.1063/1.92150

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

An intracavity image upconversion system, using a proustite crystal and a flashlamp‐pumped dye laser, is described. Experimental results regarding the spatial resolution of the system are also presented, and the conversion efficiency is discussed.

ISSN:0003-6951    

DOI:10.1063/1.92151

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Second‐harmonic light generated by mixing oppositely propagating guided waves in LiNbO3waveguides was enhanced ∼500‐fold by varying the refractive index of the medium above the LiNbO3surface.

ISSN:0003-6951    

DOI:10.1063/1.92152

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

LiNbO3surface‐acoustic‐wave edge‐bonded transducers have been fabricated on ST quartz and ⟨001⟩ cut GaAs substrates. Efficient transduction has been demonstrated with fractional bandwidths of 50 and 91% for the ST quartz and GaAs substrates, respectively. The devices have a center frequency in the vicinity of 100 MHz. Conversion loss as low as 4 dB has been measured. A model which accurately predicts this transducer performance has been devised.

ISSN:0003-6951    

DOI:10.1063/1.92153

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The optogalvanic effect is proposed and demonstrated as a new technique for quasiresonant Penning ionization spectroscopy in a discharge plasma of mixtures of rare gases and metal vapors. A calcium and neon mixture is used as a prototype. Neon’s lowest metastable level,3P2at 134 034 cm−1, is withinkTfrom the excited state of2D3/2,5/2of Ca+. Thus Penning ionization occurs to an excited state of the ion. This process strongly alters the optogalvanic signal and has its own signature. In fact, other energy transfer processes should also change the time dependence of the optogalvanic signal.

ISSN:0003-6951    

DOI:10.1063/1.92154

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A general reduction of threading dislocations over a large area of a Te‐doped InP layer, grown on (001) InP:Fe by vapor phase epitaxy has been observed in the presence of interfacial misfit dislocations. However, near the edge of the epi‐layer, the dislocation density increases considerably. These observations have been rationalized in terms of the misfit stress‐induced glide of the threading dislocations. The estimated misfit strain is ∼0.2% and evidently results from stoichiometry mismatch between the epi‐layer and the substrate.

ISSN:0003-6951    

DOI:10.1063/1.92155

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Previous work on photoacoustic spectroscopy (PAS) of semiconductors has been restricted to material in powder form. This letter shows that PAS can also be used to study intrinsic and extrinsic (impurity) absorption of semiconductors in bulk, single‐crystal form. For GaAs (Cr) the technique can easily detect Cr impurities at 5×1016cm−3level. The effects of surface preparation on the spectra are discussed.

ISSN:0003-6951    

DOI:10.1063/1.92156

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A scanned cw Ar+laser was used to anneal the polycrystalline silicon on nitride structures. Laser power varied from l0 to 15 W in increments of 1 W, the beam diameter was ∼40 &mgr;m and the scan rate was ∼12.5 cm/s. The measured field‐effect electron mobility of the metal‐oxide semiconductor field effect transistor fabricated on the annealed silicon increases with increasing laser power. In transistors annealed at power ⩽11 W, an intercrystalline potential barrier resulting from the electron trapping at crystallite and grain boundary regions was found to be the dominant factor in the channel electron conduction. In transistors annealed at power ⩾ 12 W, channel conduction is limited by scattering from surface structure imperfections.

ISSN:0003-6951    

DOI:10.1063/1.92157

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Epitaxial metastable (GaSb)1−xGexalloys with compostions across the pseudobinary phase diagram have been grown on (100) GaAs substrates by multitarget rf sputtering. An essential feature allowing the growth of these metastable materials was low‐energy ion bombardment of the growing film during deposition to enhance surface diffusion, promote mixing, and preferentially sputter incipient second‐phase precipitates. Annealing experiments indicated that the metastable films exhibit good high‐temperature stability and that they transform through a continuous series of GaSb‐rich and Ge‐rich phases in which the solute concentrations decrease until the equilibrium two‐phase alloy is obtained. While the calculated free‐energy difference between the single‐phase metastable and equilibrium states is ∼18 meV, the measured activation barrier for the transformation is ∼3 eV. All films werep‐type with room‐temperature hole concentrations varying from 1016to 1019cm−3and mobilities between 10 and 720 cm2/ V s, depending on film composition.

ISSN:0003-6951    

DOI:10.1063/1.92158

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Data are presented showing that Zn diffusion into an AlAs‐GaAs superlattice (41Lz∼45‐A˚ GaAs layers, 40LB∼150‐A˚ AlAs layers), or into AlxGa1−xAs‐GaAs quantum‐well heterostructures, increases the Al‐Ga interdiffusion at the heterointerfaces and creates, even at low temperature (<600 °C), uniform compositionally disordered AlxGa1−xAs. For the case of the superlattice, the diffusion‐induced disordering causes a change from direct‐gap AlAs‐GaAs (Eg∼1.61 eV) to indirect‐gap AlxGa1−xAs (x∼0.77,EgX∼2.08 eV).

ISSN:0003-6951    

DOI:10.1063/1.92159

出版商:AIP    

年代:1981

数据来源: AIP