摘要:

Metalorganic magnetron sputtering has been used to deposit polycrystalline and homoepitaxial films of indium antimonide. In this technique a metal antimony target is magnetron sputtered in a reactive vapor of trimethylindium (TMI). Stoichiometric layers of indium antimonide could be deposited for all growth temperatures studied (20–370 °C). However, below 250 °C the films were either amorphous or composed of very small crystallites. Above 290 °C the layers were epitaxial as determined from the electron channeling patterns observed. For these layers the growth rate was controlled by the TMI flow with the excess antimony flux acting to stabilize the surface. The surface morphology was excellent with ‘‘mirrorlike’’ surfaces except at high TMI flows where indium surface droplets were formed.

ISSN:0021-8979    

DOI:10.1063/1.337084

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A detailed comparison of two‐dimensional near‐infrared absorption maps and x‐ray topographs of commercial semi‐insulating (100) GaAs wafers grown by the liquid‐encapsulated Czochralski technique is reported. The absorption measurements with a spatial resolution up to 100×100 &mgr;m2were performed using a highly sensitive silicon diode array as the detector element. Fluctuations of the EL2 concentration up to 60% are found in conventional undoped wafers. In preannealed wafers, these fluctuations are reduced by a factor of 2, approximately. The spatial one‐to‐one correlation of the EL2 distribution with grown‐in dislocation networks, which is observed in both cases, is discussed. In indium‐doped wafers of low dislocation density, the homogeneity of EL2 is better than 5% in the central area of about 40 mm in diameter. By investigating the EL2 distribution near peripheral slip lines, it is definitely established that gettering is a relevant process leading to nonuniformities.

ISSN:0021-8979    

DOI:10.1063/1.337768

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The oxidation behavior of Fe50Ni50alloy foils implanted with 80‐keV N+2ions at a dose of ∼1016ions/cm2is studied by using the technique of conversion electron Mo¨ssbauer spectroscopy (CEMS). The oxidation is carried out in air at various temperatures up to a maximum of 500 °C, for different intervals of time. It is shown that the as‐implanted as well as implanted and annealed foils exhibit higher resistance to oxidation as compared to the virgin foils; the oxidation resistance being significantly higher in the case of the annealed foils. It is established that the reason for improvement in oxidation resistance is nickel enrichment of the surface layers leading to formation of diffusion‐limiting nickel‐rich NixFe3−xO4phase at the oxide‐metal interface during the early oxidation process. The presence of this phase in the oxidized samples is inferred from the hyperfine interactions exhibited by the corresponding CEMS spectra and also from x‐ray diffraction measurements.

ISSN:0021-8979    

DOI:10.1063/1.337769

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The permittivity of brine‐saturated porous rocks below 2 GHz varies with frequency in a way that is linked closely to the pore geometry. The theories of bounds of the permittivity by Bergman and by Milton, based on Bergman’s work on two‐component composites, impose restrictions on this frequency dependence. We give a detailed and systematic analysis of these restrictions for this special case. We show to what extent the conductivity at low frequencies, combined with a measured value of the permittivity at an intermediate frequency, restricts the permittivity at all other frequencies. We establish a scaling law, according to which the permittivity depends on the brine conductivity &sgr;2and the frequency &ohgr;, only through the ratio &sgr;2/&ohgr;, to a good approximation. We apply the analysis to data on sandstones by Poley, Nooteboom, and de Waal. As a further application of this theory, we derive bounds for the electrical or thermal conductivity of a two‐component composite using the values that this same property would have if either of the components were an insulator.

ISSN:0021-8979    

DOI:10.1063/1.337770

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Selected‐area liquid‐phase epitaxy of garnet films has been achieved through local substrate damage caused by ion implantation before film deposition. Thus, patterning with a geometrical resolution of a few microns of some micron‐thick epitaxial garnet films is possible. Film patterns are defined by ‘‘perfect’’ epitaxial film regions grown on unimplanted substrate areas and defective film regions where the substrate has been implanted before film deposition. The films produced consist either of imperfect monocrystalline film areas, film areas resulting from island growth, or of substrate areas without overgrowth. Application of the method to the growth of epitaxial (Gd,Bi)3(Fe, Ga,Al)5 O12films permits local magnetic switching of the magnetization direction confined to ‘‘perfect’’ film regions without switching of the adjacent imperfect film area.

ISSN:0021-8979    

DOI:10.1063/1.337771

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The proper elastic equations for an epitaxial bilayer system are presented, amending an earlier paper published by other authors in this journal. The stress profile normal to the surface and the radius of curvature are given as functions of the epitaxial mismatch.

ISSN:0021-8979    

DOI:10.1063/1.337772

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

New solitary electromagnetic wave solutions of Maxwell’s equations are obtained. Brittingham [J. Appl. Phys.54, 1179 (1983)] calls them focus wave modes.

ISSN:0021-8979    

DOI:10.1063/1.337773

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

NdDyFe14B shows a spin reorientation aroundTS=92 K which is lower than that obtained for Nd2Fe14B (150 K). Neutron diffraction on powder specimen indicates a preferential occupation for Dy atoms of the 4 fsites, but does not reveal the spin reorientation.

ISSN:0021-8979    

DOI:10.1063/1.337748

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The lifetime &tgr; of theR1fluorescence line,2E(E¯)→4A2of ruby (Al2O3:Cr3+) has been measured under high‐pressure conditions (up to 42.7 GPa) using a modulation fluorometry technique. This study shows that &tgr; increases linearly with pressure and that this increase is primarily caused by a rapid decrease in the transition probability of the radiative transition. The present measurements agree qualitatively with the theoretically predicted decrease in the oscillator strength at high pressure.

ISSN:0021-8979    

DOI:10.1063/1.337749

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

It was found that strong bonding takes place when a pair of clean, mirror‐polished silicon surfaces are contacted at room temperature after hydrophilic surface formation. Bonding strength reaches the fracture strength of silicon bulk after heating above 1000 °C. Electric resistivity at the interface is less than 10−6&OHgr;/cm2. Bondingp‐type silicon ton‐type silicon forms a diode. The reaction between silanol groups formed on the surface may cause the bonding force. Heating above 1000 °C was thought to diffuse oxygen to inside the silicon bulk, forming an epitaxial‐like lattice continuity at the interface.

ISSN:0021-8979    

DOI:10.1063/1.337750

出版商:AIP    

年代:1986

数据来源: AIP