摘要:

By impinging a beam of O+2ions of energy 150 eV<E<1 keV on a Si(100) surface, we produced oxide films of varying thickness at room temperature. We find that the Si—O bond features of the films are quite similar to those of a thermally prepared vitreous SiO2glass. We further observe that an intermediate range order in the form ofn‐member ring clusters withn=4 andn=6 exists in the resulting films.

ISSN:0021-8979    

DOI:10.1063/1.348565

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The parameters of electrically active defects created during the technological fabrication process of Ti‐W/nSi Schottky diodes are studied by deep level transient spectroscopy (DLTS). Using a self‐consistent simulation model and trap parameters extracted from DLTS measurements, current‐voltage characteristics of these diodes are simulated. It is found that a very satisfactory fitting can thus be obtained.

ISSN:0021-8979    

DOI:10.1063/1.348532

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Hydrogen passivation of GaAs grown on InP substrates by molecular‐beam epitaxy has been performed. Photoluminescence studies show that two peaks at 1.503 and 1.462 eV, which have the luminescence intensities in heteroepitaxial GaAs stronger than that in homoepitaxial GaAs, are effectively passivated by atomic hydrogen. The copper‐arsenic vacancy complex associated recombination is also eliminated after hydrogenation. However, hydrogenation can enhance the intensity of donor toC(As) acceptor transition. In addition, we show that the damaged surface during hydrogenation using rf glow‐discharge method can be passivated by the hydrogenation using photochemical vapor deposition system.

ISSN:0021-8979    

DOI:10.1063/1.348533

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

An ellipsometric study of the growth of hydrogenated amorphous silicon/hydrogenated amorphous silicon‐carbon interfaces and multilayer structures is presented. Kinetic ellipsometry is used at a fixed wavelength to study the growth of the materials at the interface between thea‐Si:H anda‐Si1−xCx:H layers as a function of the carbon content. It is observed that for samples with carbon content below 36%, thea‐SiC:H grows uniformly on top of thea‐Si:H. However, as the carbon content is increased beyond this point, the growth of the alloy material becomes nonuniform. Various growth models were used to fit the experimental data and the best fits were obtained using a multilayer model of varying void fraction to describe the inhomogeneous growth. Multilayers were grown usinga‐Si:H anda‐SiC:H. It was observed that for low carbon concentrations (x<0.36), the successive layers of the multilayer structure are reproducible and the growth remains homogeneous for all the layers.

ISSN:0021-8979    

DOI:10.1063/1.348534

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We investigate the optical properties of new ‘‘superlattice particles’’ that can be made of precisely controlled metal‐insulator layers fabricated by sputtering or evaporation techniques. We found that there are two limits to the reflectivity behavior corresponding to wide and narrow particles. In the narrow‐particle limit, a series of sharply defined absorption peaks at frequencies controlled by the width is observed. In the wide‐particle limit, most of the light incident on the particles will be absorbed. Materials of this type possess desirable infrared absorption characteristics and can be used for new polarization sensitive infrared absorbers and detectors.

ISSN:0021-8979    

DOI:10.1063/1.348535

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The conversion efficiency into kilovolt line radiation for 248‐nm light at 1017W/cm2on an aluminum target is measured. The x‐ray yield is found to increase with the scale length of the target plasma. The interaction is modeled as resonance absorption, and the plasma scale length is determined from the prelase energy and irradiance.

ISSN:0021-8979    

DOI:10.1063/1.348536

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Bulk laser damage threshold of 2‐in.‐diam. MgO‐doped LiNbO3crystals grown using the Czochralski technique has been measured using aQ‐switched Nd3+:LiYF4laser. The threshold showed dependence on the crystal quality. The highest bulk laser damage threshold (14 J/cm2at 1.053 &mgr;m wavelength with 1‐ns pulse width) was obtained in the LiNbO3crystal doped with 1 mol % of MgO. The lowering of bulk laser damage threshold was observed in the crystals doped with MgO at more than 3 mol %. These crystals contained the local aggregations of MgO which increased the scattering centers and decreased the transparency.

ISSN:0021-8979    

DOI:10.1063/1.348537

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Nonlinear contributions to thermoelectricity are studied when large temperature gradients are present in metals. A theory is presented to account for these phenomena in the case of monovalent metals obeying a parabolic dispersion law. Simple experiments are proposed in which nonlinear terms are relevant and produce measurable effects.

ISSN:0021-8979    

DOI:10.1063/1.348984

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

In0.2Ga0.8As/GaAs strained layer superlattices were grown by molecular‐beam epitaxy with various GaAs barrier thicknesses to study how this affects the properties of nominally 90‐A˚‐thick InGaAs wells. Double‐crystal x‐ray diffraction, photoconductivity, and photoluminescence gave similar results regarding superlattice degradation with decreasing barrier thickness. The optical measurements showed that at 58‐A˚‐GaAs thickness, the strained layer superlattice was relaxed with concomitant deterioration of its optical properties.

ISSN:0021-8979    

DOI:10.1063/1.348982

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We report numerical simulations of typical experimental conditions under which current‐voltage (I‐V) measurements of resonant‐tunneling diodes are conducted. We find that curve tracer measurements can cause bistability and hysteresis in the negative differential resistance (NDR) region. We also find that dc measurements can produce oscillations which distort the shape of theI‐Vcurve. When the series resistance is large, there are three states for a given bias in the NDR region because of the folding of theI‐Vcurve. We believe this phenomenon, extrinsic tristability, to be the source of extrinsic bistability.<lz> <lz> <lz>

ISSN:0021-8979    

DOI:10.1063/1.348961

出版商:AIP    

年代:1991

数据来源: AIP