摘要:

Growth of InGaAs lattice matched to InP was achieved for the first time on the (100) orientation of InP by liquid‐phase epitaxy. Growth conditions and melt composition for such a growth are presented. In0.53Ga0.47As/InP and InP/In0.53Ga0.47As/InP heterojunction structures for 1.7‐&mgr;m field‐assisted photocathodes have also been fabricated on (100) InP substrates.

ISSN:0003-6951    

DOI:10.1063/1.89803

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Thin films formed by organic molecules with dipoles may switch at a threshold voltage; the switching is due to the flip‐flop of the dipoles. Theoretically derived equations agree well with the experiment.

ISSN:0003-6951    

DOI:10.1063/1.89804

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

A new photorefractive effect resulting from the interaction of high‐intensity short‐duration laser pulses with propagating acoustic waves has been found to occur in LiNbO3. The index‐of‐refraction change (&dgr;n) is proportional to the rf signal and increases sublinearly with the number of laser pulses and as the 1.3 power of the incident laser energy density (J) per pulse. The decay time of &dgr;nvaries from a few hours when only green illumination (530 nm) is used to several weeks when combined green and infrared illumination (1060 nm) are used. This acoustophotorefractive effect can be utilized to construct an acousto‐optic memory correlator.

ISSN:0003-6951    

DOI:10.1063/1.89781

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

A new acoustoelectric phase shifter is proposed which produces a direct phase shift of a SAW on piezoelectric substrate. Computations of the attenuation and phase lag versus resistivity due to a silicon wafer air‐gap coupled toyz‐LiNbO3are presented. The use of the variation of the resistivity of the silicon to control the phase of a SAW was demonstrated using the photogeneration of carriers and the field‐effect control of the surface resistivity. A 180° shift was obtained with a +30‐V transverse voltage pulse.

ISSN:0003-6951    

DOI:10.1063/1.89805

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Experimental results are presented which show that the nonideal nature of electrical characteristics derived from metal‐ZnO‐SiO2‐Si structures, structures of the type proposed in surface‐acoustic‐wave applications, is due in large part to a deterioration of the Si‐SiO2subsystem during the thin‐film ZnO deposition procedure. The thermally assisted breaking of surface‐state bonds and radiation damage are identified as the sources of the deterioration. Progress achieved to date in reducing the cited damage, including the use of radiation‐hardened SiO2films and a low‐temperature O2anneal, are also described and discussed.

ISSN:0003-6951    

DOI:10.1063/1.89806

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

The normal‐incidence reflection spectrum of a tapered highly reflective (∼95%) surface‐wave grating is found experimentally and theoretically to have high sidelobes due to the taper‐induced spatial variation in the local Bragg frequency. In order to successfully use tapering for reflection sidelobe suppression, the Bragg‐frequency variation is compensated by varying the grating period. Experimental results are presented for the reflection of surface acoustic waves from metal dot arrays onyz‐LiNbO3at ∼145 MHz. The taper‐induced distortion of the reflection spectrum is expected to occur in corrugated optical waveguide reflectors as well.

ISSN:0003-6951    

DOI:10.1063/1.89807

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

During a study of the homoepitaxial growth of Si on Si(111), we have found that stacking‐fault densities in the deposited Si films decreased by two to three orders of magnitude above a ’’critical’’ substrate deposition temperature, 1250 °C. Nucleation of stacking faults in the deposited films is correlated, via SEM observations and infrared absorption measurements, with the presence of SiC protuberances on the substrate surface. We propose a simple model for SiC cluster growth (and decay) which explains the rapid decrease with temperature of the amount of SiC formed on the Si surface.

ISSN:0003-6951    

DOI:10.1063/1.89808

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

The behavior of TiO2and SrTiO3photoanodes in cells for the photoelectrolysis of H2O has been investigated for high‐intensity 351 364‐nm excitation from an Ar ion laser. Intensities up to 380 W/cm2have been used. For TiO2a small amount of surface decomposition is found after irradiation at high intensity, whereas SrTiO3undergoes no detectable changes. Current‐voltage properties for both electrodes are essentially independent of light intensity up to the level of 380 W/cm2, and there is little if any change in quantum efficiency for electron flow. Photocurrent densities have been shown to exceed 5 A/cm2for O2evolution. Data show that the energy storage rate associated with the SrTiO3photoelectrolysis can exceed 30 W/cm2; this represents the highest demonstrated rate of sustained optical to chemical energy conversion.

ISSN:0003-6951    

DOI:10.1063/1.89809

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

The expansion of laser‐produced plasma is determined from the shapes of spectral lines of highly ionized iron emitted in the extreme ultraviolet. The plasmas were produced by focusing the pulse from a Nd : glass laser onto solid planar targets, and spectra were recorded with a high‐resolution grazing incidence spectrograph. From the Doppler broadening of lines of Fe XX and Fe XXI, expansion velocities of ∼830 km s−1were determined. The relative time‐averaged ion abundances of Fe XVIII, Fe XIX, Fe XX, and Fe XXI are estimated for three different spectra. The abundances do not differ by more than a factor of 4 for any of the spectra.

ISSN:0003-6951    

DOI:10.1063/1.89782

出版商:AIP    

年代:1977

数据来源: AIP

摘要:

Earlier work described a polarization‐dependent radiation force for laser radiation interacting with a magnetized plasma. A new derivation, based on the upper‐hybrid mode, shows that this force has a resonant enhancement and implies its relation to a magnetic type of resonant absorption.

ISSN:0003-6951    

DOI:10.1063/1.89783

出版商:AIP    

年代:1977

数据来源: AIP