摘要:

Trapping centers produced by 250‐keV, 400‐keV, 700‐keV, and 1.5‐MeV proton irradiations at room temperature in AlGaAs‐GaAs solar cells have been studied. The traps detected by deep‐level transient spectroscopy are the same as those produced by electron irradiations, only their introduction rates are different. An introduction rate was determined for each trapping center at the various proton energies. The large concentration of theE4 trap suggests it is associated with a cluster‐type defect.

ISSN:0021-8979    

DOI:10.1063/1.335255

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

A comparison of the electron paramagnetic resonance spectra obtained in fast neutron‐ and electron‐irradiated GaAs crystals has confirmed the simultaneous presence of the quadruplet and singlet spectra, ascribed previously to As4+Gaand V2−Gacenters. Only in electron‐irradiated material, however, are both signals separated by the selective microwave power saturation of the quadruplet. This apparent disparity is ascribed to a difference in the coupling between the two partners in the As4+Ga‐V2−Gaassociated complexes.

ISSN:0021-8979    

DOI:10.1063/1.335256

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

The first results on high‐resolution electron‐microscope observations of unsupported amorphous germanium films, crystallizedinsituby pulsed laser irradiation, are presented. They provide new information on structure and perfection of the as‐grown crystals and on the morphology of the crystal‐amorphous interface. It is shown that, after crystallization, amorphous regions can exist as inclusions among dendrites. The structure of the crystal‐amorphous interface depends on its crystallographic orientation and is probably related to the degree of relaxation of the amorphous phase in its immediate vicinity.

ISSN:0021-8979    

DOI:10.1063/1.335257

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

When exposed to pulsed ionizing radiation, quartz oscillator crystals can exhibit transient acoustic losses (a decrease inQ) and transient frequency shifts. Although these changes are usually most pronounced in unswept quartz, they have also been seen in swept quartz. We have directly measured the transient acoustic loss in both synthetic and natural quartz. The synthetic quartz samples included hydrogen and lithium swept units. Irradiations were accomplished at REBA, a flash x‐ray facility at Sandia Laboratories. Log decrement acoustic loss measurements were made over the 110–400 K temperature range and show a time dependence similar to at−1/2behavior characteristic of one‐dimensional diffusion. The transient loss showed a broad temperature dependence ascribed to alkali ions moving along theZ‐axis channels. Peaks at 360 and 380 K in the transient loss temperature spectra are thought to be due to an unstable defect which momentarily traps the alkali ion.

ISSN:0021-8979    

DOI:10.1063/1.335258

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Diffusion profiles and the solubility of Cu in Ge were measured in the temperature interval 850–1200 K by means of the spreading‐resistance technique. From these data it is concluded that the diffusion of Cu in Ge involves the interchange between a highly mobile interstitial configuration, Cui, and a practically immobile substitutional configuration, Cus, with the aid of vacancies,V, via the so‐called dissociative mechanism, Cui+V&rlarr2;Cus. The excellent agreement of the values of the vacancy contribution to the tracer self‐diffusion coefficient in Ge, as calculated from our diffusivity and solubility data on Cu in Ge, with directly measured values of the71Ge tracer self‐diffusion coefficient from the literature demonstrates that self‐diffusion in Ge occurs via vacancies. A comparison with the mechanisms of Au and self‐diffusion in Si is presented.

ISSN:0021-8979    

DOI:10.1063/1.335259

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

The diffusion of In and Tl implanted into SiO2has been investigated by means of Rutherford backscattering spectrometry. The diffusion of these elements is shown to be strongly dependent on their chemical state in SiO2. By combining these results with previous results for Ga, a general model has been formulated which describes the incorporation and diffusion of Group III elements in SiO2. The most important parameter of this model is the valence state of these elements in SiO2. In their trivalent state these elements are incorporated on Si sites of the SiO2network, where they are virtually immobile. On the other hand, interstitial monovalent Group III ions are observed to show rapid diffusion. In addition to this, there is a second independent diffusion process, which is attributed to interstitial migration of InOH or TlOH molecules. After high‐temperature annealing of SiO2covered with Si3N4, the In and Tl diffusion profiles exhibit a peak at the SiO2‐Si interface. This segregation is tentatively explained by stress relief at the SiO2‐Si interface.

ISSN:0021-8979    

DOI:10.1063/1.335260

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

The permeation characteristics of deuterium in several iron and nickel based alloys were measured by the gas phase breakthrough technique in the temperature range 100 to 500 °C with applied pressures ranging from 10 Pa to 100 kPa. The restriction of the gas flux imposed by surface oxides was modeled in order to evaluate the effects of surface oxide retardation of the gas flux on the effective values of the deuterium permeabilities and diffusivities in the alloys. The most permeable alloys were 430 and 431 stainless steels. The next most permeable alloy was Monel K‐500, which exceeded the permeability of pure Ni by more than a factor of five at room temperature. The alloys with permeabilities less than pure Ni were, in order of decreasing permeability: the Inconels 625, 718, and 750, the Fe‐Ni‐Co glass‐sealing alloys Kovar and Ceramvar, and the 300‐series stainless steels. Deuterium trapping within the alloys appeared to influence the values of bulk diffusivities, which were not correlated with either the permeabilities or the chemical compositions of the alloys.

ISSN:0021-8979    

DOI:10.1063/1.335261

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

We describe the results of a novel adaptation of the volumetric technique to measurement of the pressure concentration isotherms for thin films of the palladium‐hydrogen system. The isotherm shapes are comparable to bulk being steep in the alpha and beta phases and flat in the mixed phase region. However, it is noted that the concentration onset of the beta phase is smaller than bulk and drops markedly for thicknesses less than 670 A˚. Comparison is made with quartz crystal microbalance results. We find a thickness dependence to the number of absorption‐desorption cycles required to obtain reproducible isotherms.

ISSN:0021-8979    

DOI:10.1063/1.335262

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

The formation of TiSi2thin films on silicon substrates has been investigated with several transmission electron microscope techniques. For films formed either by reacting titanium with a silicon substrate or by sintering a codeposited (Ti+Si) mixture, electron diffraction patterns show that a metastable phase—TiSi2(C49 or ZrSi2structure)—forms prior to the equilibrium phase—TiSi2(C54 structure). High‐resolution images indicate that the metastable TiSi2‐silicon interface is atomically sharp, with no ‘‘glassy membrane’’ layer present. The annealing temperature required to transform the metastable TiSi2to the low resistivity, equilibrium TiSi2increases as the thin‐film impurity content increases. Previous studies of TiSi2formation are discussed in light of these results.

ISSN:0021-8979    

DOI:10.1063/1.335263

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Interfacial reactions of iron thin films on silicon have been investigated by transmission electron microscopy. FeSi was found to form after 400 °C annealing. Small amount of Fe3Si was detected in samples annealed at 450 to 500 °C. &bgr;‐FeSi2grains were predominant with a few FeSi grains remained in samples annealed at 600 °C. &bgr;‐FeSi2was found to be the dominant phase, whereas &agr;‐FeSi2was predominant in samples annealed at 900–1100 °C in N2ambient and in vacuum, respectively. Two‐step annealings were effective in promoting the growth and improving the quality of epitaxial FeSi2. More uniform growth of epitaxial FeSi2was observed for samples annealed in vacuum than those heat treated in N2ambient. The mechanisms of epitaxial growth and the influence of impurities on the interfacial reactions are discussed.

ISSN:0021-8979    

DOI:10.1063/1.335264

出版商:AIP    

年代:1985

数据来源: AIP