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Cathodoluminescence (CL) emission of undoped MgO single crystals, after different treatments: thermochemical reduction, neutron irradiation, or quenching from high temperatures is studied in the scanning electron microscope. In thermochemically reduced samples, two peaks at about 410 and 520 nm are observed. Neutron irradiated samples exhibit an emission band centered at 390 nm. The spectra of the quenched crystals show two peaks at around 420 and 490 nm. The results are analyzed on the basis of emission from F-type centers. Es wird die Katodolumineszenz von undotierten MgO-Einkristallen nach verschiedenen Behandlungen: thermochemische Reduktion, Neutronenbestrahlung und Abschrecken, mittels Rasterelektronenmikroskopie untersucht. In den thermochemisch reduzierten Kristallen werden zwei Katodolumineszenz-Banden bei 410 und 520 nm beobachtet. Neutronenbestrahlte Kristalle zeigen eine Bande bei 390 nm und die abgeschreckten Kristalle zwei Emissionsbanden bei 420 und 490 nm. Die Ergebnisse werden auf der Basis der Emission von F-Typ-Zentren diskutiert.

Optical absorption has been used to study the impact damage in MgO and MgO:Li single crystals. The results are similar to that obtained in compressed crystals, except in MgO:Li with stable Li° defects, in which the impacts do not produce an increase of the 5.7 eV absorption band. Die Impaktschadigung in MgO und MgO:Li-Einkristallen wird mittels optischer Absorption untersucht. Es wird gefunden, das die Impakte eine ahnliche Anderung der optischen Absorption wie die plastische Verformung im Druckversuch erzeugen, auser im Fall von MgO:Li mit Li°-Defekten, in dem die Impakte nicht eine Zunahme des 5.7 eV Absorptionsbandes hervorrufen.

Cathodoluminescence and infrared absorption studies were made on polycrystalline as well as amorphous cordierite, either in the as-received state or after different thermal treatments. Emission bands centred at about 400 nm were observed in all the samples studied. Red emission bands around 650 nm were also found in samples irradiated with ionizing radiation or annealed in different atmospheres. Infrared absorption measurements were performed to estimate the glass phase and to monitor the presence of OH− ions.

Systemic lupus erythematosus (SLE) is a chronic, complex, and systemic human autoimmune disease, with both an environmental component and a heritable predisposition. Clinical studies, reinforced by epidemiology and genetics, show impressive variation in disease severity, expression, prevalence, and incidence by ethnicity and sex. To identify the novel SLE susceptibility loci, we performed a genomewide scan with 318 markers on 37 multiplex Hispanic families, using a nonparametric penetrance-independent affected-only allele-sharing method. Three chromosomal regions (12q24, 16p13, and 16q12-21) exceeded our predetermined threshold (Zlr>2.32; nominal P

Cathodoluminescence (CL) emission from as‐grown, thermochemically reduced and mechanically damaged LiNbO3 single crystals has been studied in the scanning electron microscope. Three emission bands at 410, 525, and 580 nm have been observed. The CL spectra strongly depend on the deformation at the surface region. An intense emission with its peak in the infrared region has been observed. Severe damage is induced by irradiation with the electron microscope beam at very high current intensities.

The effect of electron beam on the cathodoluminescence (CL) from MgO single crystals has been studied in the scanning electron microscope. It has been found that CL intensity and spectrum vary with irradiation time. The behaviour is discussed in terms of impurities and vacancy defects.

MgO crystals from five sources were thermochemically reduced at high temperatures. Optical-absorption measurements indicated that anion vacancies were present in all of the crystals. In addition, crystal darkening was observed and was due to a broad absorption in the visible region. The dark coloration was impurity related. Analytical transmission-electron-microscopy techniques indicated the presence of metallic precipitates that were primarily Fe in content. Microdiffraction patterns indicated that the precipitates possessed the fcc (a/sub 0/ = 3.61 A) or the bcc (a/sub 0/ = 2.89 A) crystal structure. The fcc precipitates were found to have a matrix relationship of /sub p/parallel /sub m/ and /sub p/parallel /sub m/. The bcc precipitates were found to have a relationship of /sub p/parallel /sub m/ and /sub p/parallel /sub m/.

Cathodoluminescence of thermochemically reduced MgO crystals has been studied in the scanning electron microscope. Two peaks at around 3.0eV (410nm) and 2.4eV (520nm) have been detected. The intensity evolution of these two peaks with temperature and electron beam irradiation has been recorded. The results are analyzed on the basis of emission from anion vacancies (F and F+ centers)

Cathodoluminescence (CL) emission from as-grown and indented LiNbO3 single crystals has been studied. The spectrum is strongly affected by deformation of the surface region. Three emission bands at about 410, 525 and 580nm have been observed. Irradiation with the electron microscope beam at very high current intensities causes a severe damage on the irradiated area. This effect can also be observed on the indented areas where the indentation pyramid can not be recognized after prolonged irradiation.

The CL emission in the scanning electron microscope from dislocations and subgrain boundaries is studied in MgO crystals having different impurity contents and in Fe doped crystals. It is found that iron acts as a quencher of CL from defects and that there are some differences in the CL spectra obtained from the different crystals. The results are attributed to decoration of dislocations by impurities and other point defects. Variations of spectral distribution caused by irradiation in the electron microscope are also reported. Es wird die Kathodolumineszenz KL von Versetzungen und Kleinwinkelkorngrenzen in MgO-Einkristallen mit verschiedenen Fremdstoff konzentrationen und Fe-Beimengungen mittels Rasterelektronenmikroskopie untersucht. Es wird gefunden, das Fe die KL von Defekten tilgt und das sich die KL-Spektren verschiedener Kristalle unterscheiden. Es wird angenommen, das die Beobachtungen eine Folge der Versetzungsdekoration mit Fremdatomen und anderen Punktdefekten sind. Variationen der KL-Spektren, hervorgerufen durch Elektronenstrahlung im Elektronenmikroskop, werden ebenfalls beschrieben.

Thermal evaporation is used to deposit thin films of CuZnAl on silicon substrates. For this purpose, a CuZnAl shape memory alloy is used as evaporation source. The chemical composition and the phases present in the films are evaluated at two different deposition rates: 7 and 0.2 Å/s. The thin films are heat treated to promote the diffusion of the elements and characterized by X-ray Diffraction, Energy Dispersive X-ray Spectroscopy and Scanning Transmission Electron Microscopy (STEM). It is shown that the chemical composition of the thin films is significantly different to that of the CuZnAl alloy used as evaporation source. Moreover, the films produced at 7 Å/s show a significant loss of Zn, contrary to the results obtained using a deposition rate of 0.2 Å/s. It is also observed that the composition varies across the thickness of the film, suggesting that the various alloying elements are evaporated at different rates during the deposition process. Finally the predominant phases present in the films belong to the AlxCuy family.

Deformed V-Ti alloys with 0.3-5at.% Ti have been characterized by transmission electron microscopy and X-ray diffraction. A mechanism for Ti segregation during annealing, related to the formation of deformation twins, has been identified. Energy-dispersive X-ray spectroscopy indicates strong local changes in Ti content along the twins. Samples post-deformation annealed at 1473K show Ti segregation and the formation of Ti-rich precipitates which have been identified using electron microdiffraction and X-ray spectroscopy. X-ray diffraction measurements reveal changes in the lattice parameter of the alloys induced by the Ti segregation and the precipitation processes.

The growth kinetics of the iridium silicides, IrSi and IrSi1.75 formed by RTA in vacuum has been characterized as a function of the processing temperature, up to 675°C, and annealing time for iridium films of different thickness. The sample temperature was measured using as a reference the SPE growth rate of amorphized silicon processed in the same RTA conditions. The samples were characterized by RBS, HREM, XRD and microdiffraction. RBS spectra show that the transition region between IrSi and IrSi1.75 is slightly gradual, while the interface between the IrSi and the iridium metal is sharp. The layer thickness of each silicide as a function of temperature and time was obtained from the RBS spectra. The activation energy of the diffusion coeficient of Si in IrSi and IrSi1.75 are about 1.3 eV and 3.9 eV respectively. Phase kinetics are the same for both thin and thick samples processed at the same temperature and annealing time when unreacted iridium remains in the film. However, the phase evolution is different when the annealing time is long enough to convert all the iridium metal into silicide in the thin film sample but not in the thick one. In this case, IrSil.75 is the only phase found if the annealing time is long enough. Silicides formed at 525°C consist mainly of polycrystalline IrSi, with grain size between 3 and 10 nm, and some isolated grains of IrSi 1.75. The interface between the IrSi and the Si is flat, very sharp, and well oriented grains grow from it. In order to avoid the IrSi1 75 formation and to obtain IrSi layers at reasonable rates, an RTA process at 500°C is proposed.

Iridium silicides formation by RTA in an Ar atmosphere or under vacuum has been studied for several temperatures in the range of 350–500°C. For the samples annealed in argon atmosphere, oxygen is incorporated during the RTA process, slowing down the reaction at the interface or even stopping it. In this case, no clear compound, Ir 1 Si 1 or Ir 1 Si 1.75 , could be identified neither from the RBS spectra nor from the AES profiles. On the other hand, when the anneal is performed under vacuum, silicidation takes place. In samples processed at 400°C in these conditions and processing time shorter than 45 s only the Ir 1 Si 1 compound was formed. For longer annealing time, Ir 1 Si 1.75 appeared too. At higher temperatures, even for very short processing time, Ir 1 Si 1.75 was formed.

Photoluminescence (PL) and cathodoluminescence (CL) emission of SrO single crystals are compared. The main CL band at about 510 nm appears also in the PL spectrum obtained by exciting the crystals with 300 nm light. CL has been found to be far more effective than PL to observe bands at 410 nm and 460 nm, which are attributed to surface processes.

Thermochemical reduction (TCR) at high temperatures has been performed on yttria-stabilized zirconia (YSZ), undoped and doped with Ni:Er, Co, or Pr. Investigations were carried out using optical absorption, luminescence, and analytical electron microscopy. After TCR, undoped crystals show an extinction band centered at about 1.8 eV which is attributed to Mie scattering from precipitates with an average size of 10 nm, as observed by analytical transmission electron microscopy. In crystals codoped with Ni:Er, TCR induced a broad extinction band centered at 1.3 eV beginning at 1600 K. Metallic Ni colloids contributing to Mie scattering have an average size of 100 nm. Similarly, in Co-doped crystals a broad band at 0.9 eV, emerging at 1750 K, was attributed to metallic colloids observed to have an average dimension of 200 nm. In all cases, the precipitate distribution is very inhomogeneous. These results agree qualitatively with the predictions of the Mie theory for the extinction bands associated with metal colloids embedded in the matrix. Electron microscope observations indicate that the degradation of the optical properties experienced by previously reduced YSZ crystals during oxidation at elevated temperatures is a bulk effect probably related to cavities and dislocations.

The influence of the composition and growth temperature on the strain and defect structure of Si1−xGex layers of 0.21≤x≤0.34 grown on (001) Si wafers by solid phase epitaxy is presented. The strain in the layers was measured by Raman spectroscopy and Rutherford backscattering spectrometry/channeling angular scans. The defects were analyzed using high resolution electron microscopy. Three different relaxation mechanisms have been identified and characterized. The first mechanism occurs at the layer-substrate interface of the samples by the introduction of isolated defects. It is found to be thermally activated with an activation energy of Ea=0.16 eV and a prefactor that depends on the Gecontent of the layer. This mechanism produces partial relaxation of the layers and hinders the growth of fully strained layers. The second relaxation mechanism emerges at a distance from the interface which depends on the stress in the crystallized portion of the layer. In this case, the strain relaxation is caused by stacking faults that nucleate when they are energetically feasible and propagate toward the surface of the sample during growth. At low growth temperatures, the defects are confined to the upper part of the epitaxial layers at a distance from the interface that agrees with the theoretical predictions based on the equilibrium critical layer thickness. The third relaxation mechanism is introduced at high growth temperature and is based on the gliding of the stacking faults toward the layer-substrate interface. As a result of this mechanism, the stress in the layers is reduced compared to the stress in the layers grown at lower temperatures and approaches the equilibrium value corresponding to the total layer thickness. This behavior indicates that the layers grown at low temperature, where the stacking faults are confined to the upper part, are to some extent metastable.

The cathodoluminescence (CL) from indented Fe doped MgO single crystals has been studied with the scanning electron microscope and the results have been compared with the CL from undoped crystals. As in the undoped crystals, the iron doped crystals show in the deformed regions an enhanced luminescence emission but it has been found that iron acts as a quencher of luminescence. The results indicate that in the blue emission of the deformed crystals there is not a noticeable contribution of iron. From the evolution of CL with the irradiation time in the electron microscope it is concluded that the total Fe content influences the CL emission more than the Fe3+ content.

The strain depth profiles in undoped and heavily boron-doped Si1−xGex layers with x = 0.21, 0.26 and 0.34 and thicknesses of 30–44 nm grown on (0 0 1) Si by solid-phase epitaxy (SPE) have been measured using RBS/channeling angular scans and the results have been correlated by the defect distributions observed in the samples by high resolution electron microscopy (HREM). The layers exhibit a partially relaxed defect-free region next to the layer-substrate interface for which the strain is almost constant. For the top region of the layers a decrease of the strain, which correlates well with the observation of strain-relieving defects, is found. The defect-free regions are thicker and closer to coherency to the Si substrate in the doped layers than in the undoped ones, indicating a strain compensation due to the inclusion of boron atoms.

Purpose: Tumors with low frequencies of checkpoint positive tumor-infiltrating lymphocytes (cpTIL) have a low likelihood of response to PD-1 blockade. We conducted a prospective multicenter phase II trial of intratumoral plasmid IL-12 (tavokinogene telseplasmid; “tavo”) electroporation combined with pembrolizumab in patients with advanced melanoma with low frequencies of checkpoint positive cytotoxic lymphocytes (cpCTL). Patients and Methods: Tavo was administered intratumorally days 1, 5, and 8 every 6 weeks while pembrolizumab (200 mg, i.v.) was administered every 3 weeks. The primary endpoint was objective response rate (ORR) by RECIST, secondary endpoints included duration of response, overall survival and progression-free survival. Toxicity was evaluated by the CTCAE v4. Extensive correlative analysis was done. Results: The combination of tavo and pembrolizumab was well tolerated with adverse events similar to those previously reported with pembrolizumab alone. Patients had a 41% ORR (n = 22, RECIST 1.1) with 36% complete responses. Correlative analysis showed that the combination enhanced immune infiltration and sustained the IL-12/IFNγ feed-forward cycle, driving intratumoral cross-presenting dendritic cell subsets with increased TILs, emerging T cell receptor clones and, ultimately, systemic cellular immune responses. Conclusions: The combination of tavo and pembrolizumab was associated with a higher than expected response rate in this poorly immunogenic population. No new or unexpected toxicities were observed. Correlative analysis showed T cell infiltration with enhanced immunity paralleling the clinical activity in low cpCTL tumors.

Cathodoluminescence (CL) studies in undoped spinel show that two emission bands appear: one at about 520 nm and another in the red region. The last band has structures with a maximum located at 693 nm. These bands are probably associated with excited V3+ and Cr3+ respectively.

The influence of the germanium fraction on the parameters of the solid phase crystallization of amorphous silicon-germanium has been studied. Layers of different compositions were deposited by LPCVD at 450 °C and crystallized at 525, 550, 575 and 600 °C. The crystalline fraction was determined as a function of the annealing time for each germanium fraction and temperature. The incubation and the characteristic crystallization times were obtained by fitting the crystalline fraction to Avrami's model. The values of the diffusion activation energy were obtained for different compositions. The dependence of the nucleation rate and the growth velocity on the germanium fraction and the temperature was studied. The three parameters decrease as the Ge fraction increases; though the stronger dependence corresponds to the nucleation rate. The dependences on the composition and the temperature were analyzed in the frame of a conventional nucleation and growth model and their relationship with the corresponding free energies was discussed.

A detailed characterization of undoped and heavily boron-doped Si1−xGex layers with x=0.21, 0.26, and 0.34 grown on (001) Si wafers by solid phase epitaxy is presented. The starting material for solid phase epitaxial growth was prepared by amorphization of epitaxial SiGe-Si heterostructures by ion implantation. In order to obtain doped layers, boron was also implanted into some of the amorphous samples. After regrowth, the strain depth distributions of the SiGe layers were measured using axial channeling angular scans and the defect distributions were observed by high-resolution electron microscopy. A defect-free region ranging from 0 nm (undoped layer of x=0.34) to 30 nm (doped layer of x=0.21) in thickness was observed next to the layer-substrate interface. In the upper region of the layers, strain-relieving defects, identified as planar faults, were observed. Some isolated defects were also present at the layer-substrate interfaces of most of the samples. The measured strain depth profiles show that (i...

The crystallization kinetics and film microstructure of poly-SiGe layers obtained by solid-phase crystallization of unimplanted and C- and F-implanted 100-nm-thick amorphous SiGe films deposited by low-pressure chemical vapor deposition on thermally oxidized Si wafers were studied. After crystallization, the F- and C-implanted SiGe films showed larger grain sizes, both in-plane and perpendicular to the surface of the sample, than the unimplanted SiGe films. Also, the (111) texture was strongly enhanced when compared to the unimplanted SiGe or Si films. The crystallized F-implanted SiGe samples showed the dendrite-shaped grains characteristic of solid-phase crystallized pure Si. The structure of the unimplanted SiGe and C-implanted SiGe samples consisted of a mixture of grains with well-defined contour and a small number of quasi-dendritic grains. These samples also showed a very low grain-size dispersion.