摘要:

A new method of measuring the longitudinal magneto‐optic effect has been introduced. This method does not require a modulator; instead, the analyzer is rotated and the intensity of light is collected as a function of the analyzer angle. The Fourier analysis of the intensity date versus the analyzer angle yields the information about the rotation angle and the ellipticity of the transmitted light. This method is simple in design as well as fast and accurate in data acquisition by virtue of computer‐assisted data collection. It was applied to the real samples of the optical glasses of Schott—SF2, F2, SF6, and SF10. The rotation angle was linearly proportional to the magnetic intensity and the Verdet constants showed a normal dispersion versus photon energy. The results were in a good agreement with other published values. Some possible applications of the present technique to the measurement of a very small birefringence have been discussed.

ISSN:0021-8979    

DOI:10.1063/1.345049

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Using infrared (IR) absorption measurements, it is proposed that amorphous hydrogenated silicon films obtained from plasma‐enhanced chemical vapor deposition of Silane (SiH4) highly diluted in helium at high rf‐power densities, consist of an amorphous tissue in which a columnar microstructure is embedded. The evolution of the IR spectrum with dilution evidences a remarkable tendency to the substitution of monohydrides by dihydrides. The films show high transparency and good conductivity. These properties make them suitable to be used as window layers for thin‐film solar cells when conveniently doped.

ISSN:0021-8979    

DOI:10.1063/1.346078

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Infrared photoluminescence (PL) from InSb, InAs, and InAs1−xSbx(x<0.3) epitaxial layers grown by atmospheric pressure organometallic vapor phase epitaxy has been investigated for the first time over an extended temperature range. The values of full width at half maximum of the PL peaks show that the epitaxial layer quality is comparable to that grown by molecular‐beam epitaxy. The observed small peak shift with temperature for most InAs1−xSbxepilayers may be explained by wave‐vector‐nonconserving transitions involved in the PL emission. For comparison, PL spectra from InSb/InSb and InAs/InAs show that the wave‐vector‐conserving mechanism is responsible for the PL emission. The temperature dependence of the energy band gaps,Eg, in InSb and InAs is shown to follow Varshni’s equationEg(T)=Eg0−&agr;T2/ (T+&bgr;). The empirical constants are calculated to beEg0=235 meV, &agr;=0.270 meV/K, and &bgr;=106 K for InSb andEg0=415 meV, &agr;=0.276 meV/K, and &bgr;=83 K for InAs.

ISSN:0021-8979    

DOI:10.1063/1.345050

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

In this paper the influence of electron multiplication in ZnS‐type electroluminescence ac devices is studied in a model where the ZnS layer is free from bulk defects. The holes are assumed to recombine with electrons at the interfaces: The two limiting cases of slow and fast hole‐electron recombination rate are treated in some detail. The kinetic equations for the electric field and the filling level of interface electrons are established then the charge‐voltage characteristics are obtained numerically. An anomalously steep charge‐voltage characteristic may be observed for high multiplication rates and slow recombination. In all cases the field is shown to be delayed relative to the current: This phase relationship is related to bulk ideality and allows for qualitative comparisons with experimental data.

ISSN:0021-8979    

DOI:10.1063/1.345051

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The damage produced in crystalline silicon by Ge‐ion implantation at 130 keV is studied as a function of fluence. Rutherford backscattering measurements in channeling configuration and reflectivity measurements in the 1.5–6.5 eV energy range are presented and discussed. The results obtained by both techniques are in agreement on the determination of the amorphization threshold. The dielectric functions, obtained by the Kramers–Kronig analysis and checked through ellipsometric measurements at one selected wavelength, are well reproduced by finite sets of classical harmonic oscillators. It is possible to describe the behavior of the oscillator parameters through analytical functions of a single variable related to the amount of damage. In a representative case, the damage depth profile is obtained after the removal of controlled amounts of silicon by anodic oxidation, and good agreement is found with the Rutherford backscattering results.

ISSN:0021-8979    

DOI:10.1063/1.345052

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

A finite element method has been used to study temperature profiles in multilayer semiconductor structures. Of particular interest is the modeling of a continuous wave energy beam similar to those typically used for electron, laser, or ion beam annealing of semiconductor layers. The intensity of the heat source has been modeled in the form of a Gaussian disk on the surface of the structure. Using experimental data and appropriate curve fitting, mathematical expressions are derived that model both thermal conductivity and specific heat as a function of both temperature and sample composition. The resulting expressions give interpolation errors of less than 1% when compared with tabulated experimental values. The simulated temperature distributions are obtained by numerically solving the Helmholtz equation in cylindrical coordinates. Results are presented of simulations involving multilayer structures consisting of metal, insulating, and semiconducting films typically used in both silicon and gallium arsenide technology. The calculated temperature distributions point to possible large variations in substrate temperature as a consequence of lack of thorough control over the beam parameters. More specifically, the diameter of the energy beam is found to strongly affect the resultant peak temperature. The presence of either metal and/or dielectric layers on the surface of the semiconducting substrates is found to have a profound effect on the simulated temperature distributions.

ISSN:0021-8979    

DOI:10.1063/1.345053

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

An infrared (10 &mgr;m) wave front is recorded holographically on a dynamic recording medium consisting of a thin oil film on a glass substrate. The phase hologram obtained is used to restore the information of the infrared wave front or alternatively as a diffraction grating for a visible reconstruction beam. This property is applied to implement a single hybrid interferometer (Michelson or Mach–Zehnder) for the simultaneous testing of infrared and/or visible optical components. Experimental results for both visible and infrared components (parallel plate, lens) confirm the usefulness of this interferometer.

ISSN:0021-8979    

DOI:10.1063/1.345054

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Hydrogenated amorphous silicon carbide (a‐SiC:H) films were deposited with a radio‐frequency plasma‐enhanced chemical vapor deposition system which utilizes a dc electric field applied independently of the inductively coupled rf field. The source gases were SiH4and CH4. It was found that application of an electric field directed out of the substrate surface enhances the growth rate and yields some improvements in photoconductivity. The compositions of the films were evaluated by x‐ray photoelectron spectroscopy for a range of source gas mixtures. In order to assess the applicability ofa‐SiC:H thin films, heterojunctiona‐SiC:H/crystalline Si (c‐Si) diodes were fabricated and their electrical characteristics evaluated. The diode capacitance‐voltage results confirmed a step junction, which was consistent with the abruptness of the interface demonstrated by high‐resolution transmission electron microscopy. The heterojunction diodes also showed good rectifying properties, suggesting promise fora‐SiC@B:H in device applications.

ISSN:0021-8979    

DOI:10.1063/1.345055

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The static conductivity and dielectric constant of two‐component periodic composite material are calculated using the Fourier expansion technique. The composite material consists of spheres that are arranged in simple, face‐centered, or body‐centered cubic lattices. The spheres may be isolated to yield high porosity or pore space, or they may intercept each other, leaving small pore space in between. The effective static conductivity and dielectric constant of such structures are computed theoretically when the pore space is filled with a material that has a conductivity or dielectric constant which differs from that of the matrix of the structure.

ISSN:0021-8979    

DOI:10.1063/1.345056

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The ionized cluster beam technique (ICB) is under development as a thin‐film deposition method. The key difference between ICB and other techniques is that the material to be deposited is said to arrive at the substrate in the form of ionized, accelerated atom clusters, previously reported to average 1000 atoms in size. A number of advantages have been attributed to ICB depositions including low‐temperature epitaxy, epitaxy for materials with a relatively large lattice mismatch, low surface damage, and near bulk density. However, for the majority of depositions reported, the beam cluster state was not measured directly but inferred from theory. Consequently, little is known about the conditions required for significant cluster formation and how clusters influence film properties. The purpose of this study was to investigate the cluster state of a gold beam in a Kyoto University ICB deposition instrument. Electrostatic deflection experiments showed no significant cluster formation over the full operating range of the instrument.

ISSN:0021-8979    

DOI:10.1063/1.345057

出版商:AIP    

年代:1990

数据来源: AIP