摘要:

The Hg content of anodic sulfide films on Hg1−xCdxTe (MCT) were investigated for as‐grown and heat‐treated films by using 30–40‐MeV O5+ion backscattering. Heat treatments were performed in a vacuum for 60 min at various temperatures up to 300 °C for the samples withx=0.20 and up to 350 °C for the samples withx=0.30 and 0.35. A significant Hg content of about 15 at. % of Cd was found in the as‐grown anodic sulfide film on MCT samples withx=0.20, 0.30, and 0.35. After heat treatment above 260 °C forx=0.30 and 0.35 and above 210–240 °C forx=0.20, the Hg atoms were removed from the films, and Hg deficient layers were formed near the interface region of the MCT crystal. This suggests that the residual Hg in the anodic sulfide films introduced during the sulfidization process plays an important role toward the degradation of the passivation properties of the sulfide film on MCT.

ISSN:0021-8979    

DOI:10.1063/1.340480

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

The number of oxygen atoms in a thermal donor (TD) can be determined directly from the reduction of the concentration of interstitial oxygen in Czochralski (Cz) silicon after annealing at 450 °C for 75 h, when the effect of high‐carbon concentration in Si crystals is considered. It is found that on the average a single TD cluster contains eight oxygen atoms. Some TD‐inactive large oxygen clusters are produced if the annealing time is longer than the time for TDs to reach their maximum concentration or if the annealing temperature is higher than 475 °C. We also find that the smallest TD cluster contains five oxygen atoms and the largest TD cluster contains 13 oxygen atoms.

ISSN:0021-8979    

DOI:10.1063/1.340481

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

In this paper it is demonstrated that a modified coventional current density expression can be employed to model tunnel currents and to numerically fit observed characteristics. A derivation of the current density expression is presented along with numerical simulations. A detailed account is given of the numerical techniques used and an explicit comparison with previously published experimental characteristics presented. We point out that part of the experimental situation is not accounted for within the model. This gives rise to the only fitting parameter used, which physically represents a resistance in series with the resonant structure. The series resistance has important effects upon the observed characteristics, explaining the different types of published characteristics and the disappointing peak‐to‐valley ratios. The effect upon the peak‐to‐valley ratio of the series resistance means that extensive numerical calculations would be premature; therefore, a qualitative analysis is undertaken to identify the desired properties of a resonant tunneling potential in order to assist in the design of future resonant tunneling systems. Finally, the hot electron spectrometer is considered. The work indicates that this spectrometer will only yield meaningful results if extreme care is taken in its operation and interpreting the results obtained.

ISSN:0021-8979    

DOI:10.1063/1.341158

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

The growing conditions and the basic interface properties of InP‐sulfide‐metal structures formed by direct and indirect plasma‐enhanced sulfidation were investigated. The grown‐in sulfide layer is an admixture of InPS4and In2S3. The relative concentration of the low‐gap indium sulfide is responsible for the high leakage currents (10−3A cm−2) in the direct plasma layers. In the indirect plasma case the leakage currents are reduced to 10−6A cm−2with breakdown voltages about 7×106V cm−1. The current transport and the frequency dependence of the capacitance of these diodes are consistently attributed to traps located in the sulfide near the semiconductor (SC) surface with a concentration in the 1011cm−2range. Detailed measurements of the capacitance‐voltage characteristics reveal that the Fermi level in InP is swept through the upper half portion of the band gap and that accumulation and strong depletion regimes are reached. These measurements also reveal that the room‐temperature hysteresis‐freeC‐Vplots result from the compensative effects of mobile charges in the sulfide and of charges trapped on the interface states. Separation is made by freezing the mobile charges either in the nearby InP or Au electrode region and the interface states in the empty or in the filled state. Induced shifts in theC‐Vcharacteristics allow a direct access to both concentrations which are in the high 1011cm−2range. The energy density of interface states is calculated in two ways from theC‐Vplots and directly measured by deep‐level transient spectroscopy. The energy density is equal to ∼1.1012cm−2 eV−1fromEctoEc−0.6 eV and then increases to 7–8×1012cm−2 eV−1nearEc−0.7 eV.

ISSN:0021-8979    

DOI:10.1063/1.340482

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

The interaction of microwaves with superconductors was explored via extensive measurements of the surface resistanceRsand reactanceXsat 10 GHz of superconducting Sn. The measurements were carried out as functions of thicknessdand temperatureTfor Sn films ranging in thickness from 190 A˚ to bulk. By varying the thickness with accompanied variation of mean free path, we were able to examine the wave‐vector dependence of the microwave‐superconductor interaction. An analysis, based on the Bardeen–Cooper–Schrieffer electrodynamical kernel, was developed for calculatingRsandXsas functions ofd,T, and frequency. Details of the measurement techniques and analysis are presented. Experiment and theory agree excellently, with no adjustable parameters. For films withd<800 A˚ we find that the electrodynamics is local because of impurity scattering, while for thicker films nonlocal effects are important. The results imply that superconducting films with microwave response that agrees with theoretical expectations can be fabricated for potential applications in a variety of superconducting structures.

ISSN:0021-8979    

DOI:10.1063/1.340483

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

The influence of local crystalline defects upon the magnetization reversal process of single‐crystalline iron whiskers has been investigated by direct observation of the domain configuration and by inductive magnetization measurements. As an essential result, the investigations bring to evidence that only weak interactions are obtained between the dislocations and 180° Bloch walls. On the other hand, a strong pinning efficiency to 90° Bloch walls is observed which is due to the stress field created by the perturbation.

ISSN:0021-8979    

DOI:10.1063/1.340484

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

A systematic study of the magnetic properties of the system Y1−xPrxCo5has been carried out in order to clarify the respective role of 3dand 4fanisotropy in the occurrence of first‐order magnetization processes (FOMP) and spin reorientation transitions (SRT) in PrCo5. The competition between Co and Pr anisotropies is responsible for the occurrence of SRT and FOMP, which is indeed observed in Pr‐rich samples. The SRT and the onset FOMP temperatures both increase with increasing Pr content. The anisotropy field, measured by the SPD technique, increases linearly with increasing Pr content. This behavior is not expected and not explainable in terms of a simple addition of Co and Pr anisotropies. A comparison is made with the anisotropy in the systems Y2Co14B and Pr2Co14B.

ISSN:0021-8979    

DOI:10.1063/1.340485

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

This paper presents an analysis of the static losses due to the irreversible Barkhausen jump of the 180° Bloch wall separating infinitely large domains. A relation between the area swept by the wall and the corresponding duration of the jumps is obtained both on the basis of considerations of the pressure acting on the wall and by direct calculation of the energy loss. A similar problem was considered by Allia and Vinai, who adopted a simplified assumption of the domain of an infinitely long cylindrical shape.

ISSN:0021-8979    

DOI:10.1063/1.340486

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

The dominant carbon‐related radiation damage center in silicon was studied in detail by deep level transient spectroscopy. Samples with different carbon and oxygen content were implanted with gradually increasing proton fluence. Two energetically closely spaced levels were revealed and tentative identities were assigned. One atET+EV=0.344 eV (&sgr;p=1.1×10−16cm2) is assigned as the C+Oicomplex, and that atET+EV=0.370 eV (&sgr;p=8×10−18cm2) is assigned as the Cs‐Sii‐Cscomplex. It was shown that the concentration of these defects is correlated to the total concentration of carbon in the crystal.

ISSN:0021-8979    

DOI:10.1063/1.340487

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

We have studied aluminum‐implantation enhanced intermixing of GaAs‐AlGaAs quantum‐well structures using low‐temperature photoluminescence. The energy shift of the heavy‐hole exciton was determined for Al doses varying from 2×1013cm−2to 1×1015cm−2after either furnace annealing at 800 °C or optical rapid thermal annealing at 925 °C. A variational calculation yields the diffusion length from the energy shift of the exciton. This shift is due both to the increase of Al in the center of the well and to the change in electron and heavy‐hole confinement energies. The ion‐implantation enhancement of the diffusion length depends on Al‐ion dose but not significantly on annealing time or temperature. This work indicates that Al‐ion implantation should be useful for the fabrication of structures of reduced dimensionality by patterned implantation of AlGaAs‐GaAs quantum wells.

ISSN:0021-8979    

DOI:10.1063/1.340488

出版商:AIP    

年代:1988

数据来源: AIP