摘要:

The intensity of electron-induced photon emission from Ag films of various thicknesses on W(110) has been measured as a function of the energy of the incident electrons, the emitted photons being detected in two narrow spectral intervals atℏω1= 3.83 eV andℏω2= 3.08 eV. The threshold for photon emission was found to theEp= 0 eV for both wavelengths. The measured isochromat spectra are compared to the total current spectra. Minima atE1= 16.5 eV andE2= 20 eV above the Fermi level are thought to correspond to an increase of the electron reflection from the sample surface at these energies. At the same time the maximum in theℏω= 3.08 eV isochromat spectrum atE= 6.5 eV above the Fermi level is due to the dominating radiative capture to states atE= 3.4 eV above the Fermi level. The spectral distribution ofintensity of the electron-induced photon emission was obtained for Ag films of various thicknesses at the electron energyEp= 0 eV above the vacuum level.

ISSN:1042-0150    

DOI:10.1080/10420159008213096

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The nuclear reactions15N(p,αγ)12C and15N(p,α)12C were used to determine the location and depth distributions of the implanted15N atoms in InP, InAs and InSb semiconductors. The behaviour of the implanted nitrogen atoms durings thermal treatment was also investigated. The yieldsof the15N(p, αγ)12C reaction were measured to determine the projected range of15N in AIIIBV. Nb. Ni, Zr Materials.

ISSN:1042-0150    

DOI:10.1080/10420159008213097

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The passage through a thick monocrystal of ultrarelativistic electrons has been considered including multiple scattering and asymptotic expression for particle transverseenergy distribution has been derived. It has been shown that the flux-peaking effect and an excess yield of δ-electrons occur also at large penetration depthtand are determined by the balance between dechanneling and feeding. Due to the beam angular spread these effects relax to zero as 1/√t. The absorption of δ-electrons leads to the saturation of their excess yield from a thick monocrystal in accordance with experimental measurements.

ISSN:1042-0150    

DOI:10.1080/10420159008213098

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The radiation damage after bombardment with high energy particles is believed to becaused by the displacement of atoms from their normal sites. These displaced atoms tendto return to their original positions particularly during annealing. The thermal effects caused by238U having ion beam energies 15.0 and 5.9 MeV/n were studied insodalime, phosphate and silicate glass detectors. The annealing kinetics of these radiation damaged tracks is discussed using both isochronal and isothermal processes. A modified formulation developed earlier is employed to calculate the activation energy of annealing.

ISSN:1042-0150    

DOI:10.1080/10420159008213099

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

TiO2layers on Ti have been formed by anodic polarization.Ion implantation on Pd+of 70 or 200 keV energy yields a doped amorphous oxide. Subsequent repassivation by anodization to potentials below the formation potential causes recrystallization. This recrystallization starts at the interface to the underlying metal, demonstrating for the first time solid phase epitaxial regrowth under the influence of an electrical field. In the amorphous phase the activation energyfor ion migration is sufficiently lowered to result in three times thicker oxide layersthan the original ones.

ISSN:1042-0150    

DOI:10.1080/10420159008213100

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Charge state distributions of foil transmitted MeV He ions are measured at the(100)planar chennelling in thin single crystals of Au with atomicallycleansurface under UHV conditions. It is found that the charge state distribution of foil transmittedHe ions depends on the orientation of the (100) crystal plane to the direction of the incident He+beam. Dependence of the charge state distribution on ion exit position in the (100) planar channel has been derived from the experimental data. We attribute the deduced position-dependent charge state distributions to the variation of charge exchange cross-sections of He ion on the distance of the ion from the channel walls.

ISSN:1042-0150    

DOI:10.1080/10420159008213101

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Transmission electron microscopy has been used to study the effect of ion implantation of krypton ions into cobalt. This has been found to result in the formation of a high concentration of bubbles, with those having diameters below ≈3 nm being solid at room temperature. Electron diffraction has been used to characterise these solid bubbles, or precipitates, and this has shown them to possess a hcp crystalline structure, and to exhibit an epitaxial relationship with the matrix. Bubble ordering into rafts parallel to the basal plane of the metal has also been observed, although the bubble positionwithin the rafts appeared random. These results extend the data available on inert gas precipitation in hcp metals.

ISSN:1042-0150    

DOI:10.1080/10420159008213102

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

This work is concerned with thermally stimulated depolarization current (TSDC) and ionic conductivity studies in lead fluoride containing the small rare earths Dy, Ho, Er and Yb. The TSDC scans from 80 to 300 K show two peaks. For Pb1−xErxF2+xone is located at 106 K, and another, which is much stronger, occurs at about 160 K. The former is associated with a dipolar defect containing at least two rare earths and the latter is attributed to the development of F−space charge during polarization of the sample. The activation energies obtained from both the high temperature TSDC peak and the ionic conductivity are the same, which corroborates the latter assignment. In addition, the ionic conductivity is shown to be independent of concentration. Those results can be understood of rare earth clustering, which is either absent or is unobservable dielectrically for large rare earths such as lanthanum, occurs extensively even at very low concentrations of the small rare earths. The explanation is that the majority of fluorine charge compensators are trapped by clusters.

ISSN:1042-0150    

DOI:10.1080/10420159008213103

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Working mainly on quartz crystals it has been found that crystal defects present inherently or generated deliberately on the surface and in the bulk give rise to surface voltage (called by us self-voltage) due to charged electron and hole traps produced by the defects, the self-voltage thus forming monitor of presenceof crystal defects. The self-voltage could be measured by FET instrumentation.

ISSN:1042-0150    

DOI:10.1080/10420159008213104

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor