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We report on modifications of 280-nm thin polycrystalline CrN layers caused by vanadium ion implantation. The CrN layers were deposited at 150°C by d.c. reactive sputtering on Si(100) wafers and then implanted at room temperature with 80-keV V+ ions to fluences of 1×1017 and 2×1017 ions/cm2. Rutherford backscattering spectroscopy, cross-sectional transmission electron microscopy, and X-ray diffraction were used to characterize changes in the structural properties of the films. Their optical and electrical properties were analyzed by infrared spectroscopy in reflection mode and electrical resistivity measurements. CrN was found to keep its cubic structure under the conditions of vanadium ion implantation used here. The initially partially non-metallic CrN layer displays metallic character under implantation, which may be related to the possible formation of Cr1−x V x N. [ABSTRACT FROM AUTHOR]

Abstract: Ion implantation is a promising route for doping quartz with luminescent impurity atoms and growing photoactive nanoparticles of them. The present work focuses on cathodoluminescence (CL) and epitaxy during or after Na, Rb, Cs, Ge, and Ba ion implantation as well as Rb/Ge double implantation in crystalline α-quartz, under the conditions of dynamic, chemical or laser epitaxy. In addition to the known intrinsic sub-bands in the CL spectra, which have been associated with specific defects in the silica matrix, very intense blue or violet bands were found. They are correlated with the implanted ion species and follow their thermal behaviour. The quantum efficiency and possible origins of the blue/violet CL emission for various ions and processing treatments will be discussed. The case of double Rb/Ge implantation appears to be very promising with respect to a combination of a high CL output and full chemical epitaxy. [Copyright &y& Elsevier]

Abstract: Highly textured FeCo thin films have been prepared by pulsed laser deposition on Si(100) and MgO(100) single crystals. The influence of the microstructure on the magnetic properties has been studied using the magneto-optical Kerr effect and vibrating sample magnetometry. The in-plane coercivity of the films deposited on Si and MgO was 28Oe and 12Oe, respectively. A fourfold in-plane magnetic anisotropy has been observed for a film deposited on MgO(100), in contrast to the isotropic pattern of the film deposited on Si. The films have then been irradiated under an in-plane magnetic field of 104Oe by 40-keV Ne- and 200-keV Xe-ions, at a fluence of 1×1015 ions/cm2. For Xe-ions, the film deposited on Si(100) developed a twofold magnetic anisotropy, while the film on MgO exhibited only slight changes of the fourfold anisotropy. [Copyright &y& Elsevier]

Abstract: Ion implantation used for doping quartz with photoactive impurity atoms amorphizes the matrix already at moderate fluences. Following our recent studies on dynamic, laser-induced or chemical epitaxy of ion-irradiated α-quartz, this paper focuses on the cathodoluminescence (CL) spectra obtained after Ge, Ba, Rb and double Rb/Ge ion implantation, under the conditions of dynamic or chemical epitaxy. In addition to “intrinsic” subbands in the CL-spectra, several blue and violet bands correlated with the particular implanted ion species were observed. In the case of Ba, nearly complete dynamic epitaxial growth was achieved, but not for Ge. In the case of Rb, full chemical epitaxy was obtained upon annealing in oxygen or air, but the CL output decreased above 1000K due to Rb outdiffusion. Double Rb/Ge implantation and annealing in air appears as a very promising novel route to achieve high CL light output and full recrystallization. [Copyright &y& Elsevier]

In the course of a systematic investigation of heavy ion-irradiated Fe/Si layers, we have studied atomic transport and phase formation induced by 22-keV14N2+ ion implantation in57Fe(30 nm)/Si bilayers at high fluences. We report here results obtained by Rutherford backscattering spectroscopy, X-ray diffraction, and conversion electron Mössbauer spectroscopy after implantation and post-implantation annealing treatments. The irradiations caused little sputtering, but significant interface mixing. During implantation, iron nitrides, but no silicides were formed, even at the highest nitrogen fluence of 2×1017 ions/cm2. When heating these samples in vacuo up to 700 °C, the iron-rich phases e-Fe3N and ?'-Fe4N were produced. Starting at 600 °C the silicide phase ß-FeSi2 was also identified. [ABSTRACT FROM AUTHOR]

Abstract: The luminescence properties of ion-beam doped silica and quartz sensitively depend on the ion species and fluence and the thermal processing during or after ion implantation. While no epitaxy, but a high cathodoluminescence (CL) output can be reached after dynamic Ge-ion implantation in quartz, full planar epitaxy is achieved after alkali-ion implantation (Na, Rb, Cs) under appropriate ion and annealing conditions. Now for the first time we achieved high luminescence intensity and (partial) recrystallization of α-quartz by double Ge/Rb-ion implantation. Pure synthetic α-quartz samples were irradiated with 175keV Rb-ions and subsequently with 120keV Ge-ions and post-annealed at 1170K in vacuo, air or 18O2 gas. A comparative analysis of the epitaxy (via RBS-Channeling) and cathodoluminescence was carried out, the latter showing three dominant emission bands in the blue/violet region at 2.95, 3.25 and 3.53eV, which were assigned to Rb- or Ge-implantation. For increasing CL temperature, a shift of the predominant peak from 2.95 to 3.25eV was noted after air-annealing, accompanying partial chemical epitaxy. [Copyright &y& Elsevier]

Abstract: Ion implantation and recrystallization of quartz may be a very important process for photonic applications. We have investigated how laser irradiation can be used to epitaxially recrystallize layers of α-quartz, which were amorphized by 175keV Rb+ or 250keV Cs+ ion implantation at a fluence of 2.5×1016 cm−2. The samples were irradiated with pulses of a XeCl excimer laser (wavelength 308nm, pulse length 55ns, energy density 3.2–5J/cm2). The thickness of the amorphous layer and the quality of the recrystallized layer were analyzed by Rutherford Backscattering Channeling Spectroscopy. Partial epitaxial recrystallization was found for all laser-irradiated samples that proceeded faster for higher laser energy density, however no full epitaxy was achieved up to the maximum laser energy of 5J/cm2. The degree of epitaxy was more or less the same for 20 or 200 laser shots. [Copyright &y& Elsevier]

Rectangular 75 nm thick Co films were irradiated with 200 keV Xe-ions, to fluences of 2.5×1013–8×1015 ions/cm2. The film thickness and the implanted Xe profiles, the phase structure and ion-induced lattice dilations as well as the magnetic hysteresis patterns were measured. For lower fluences up to 4×1014 Xe/cm2, we found predominantly the HCP phase with an in-plane magnetization. The transition to the four-fold in-plane magnetization typical of the FCC phase occurred at a fluence range between 4×1014/cm2 and 2×1015/cm2. [Copyright &y& Elsevier]

Abstract: Polycrystalline titanium nitride (TiN) layers of 240nm thickness and columnar microstructure were deposited at 150°C by d.c. reactive sputtering on Si(100) wafers and then irradiated at room temperature with either 80keV V+ ions (at fluences of up to 2×1017 ions/cm2) or 200keV Ar+ ions (at fluences of 5×1015–2×1016 ions/cm2). Rutherford backscattering spectroscopy, cross-sectional (high-resolution) transmission electron microscopy and X-ray diffraction were used to characterize ion-induced changes in the structural properties of the films. Their optical and electric properties were analyzed by infrared reflectance (IR) and electric resistivity measurements. After deposition, the stoichiometric TiN films had a (111) texture. Ion implantation generated a damaged surface layer of nanocrystalline structure, which extended beyond the implantation profile, but left an undamaged bottom zone of (111) orientation. This layer geometry determined from transmission electron microscopy was inferred in the analysis of IR reflectance data using the Drude model, and the variation of the electric and optical resistivity with the irradiation was deduced. The results were compared to those recently gained for ion-implanted reactively sputtered chromium nitride films. [Copyright &y& Elsevier]

Abstract: Studies on ion-irradiated transition-metal/silicon bilayers demonstrate that interface mixing and silicide phase formation depend sensitively on the ion and film parameters, including the structure of the metal/Si interface. Thin Co layers e-gun evaporated to a thickness of 50nm on Si(100) wafers were bombarded at room temperature with 400-keV Xe+ ions at fluences of up to 3×1016 cm−2. We used either crystalline or pre-amorphized Si wafers the latter ones prepared by 1.0-keV Ar-ion implantation. The as-deposited or Xe-ion-irradiated samples were then isochronally annealed at temperatures up to 700°C. Changes of the bilayer structures induced by ion irradiation and/or annealing were investigated with RBS, XRD and HRTEM. The mixing rate for the Co/c-Si couples, Δσ 2/Φ =3.0(4)nm4, is higher than the value expected for ballistic mixing and about half the value typical for spike mixing. Mixing of pre-amorphized Si is much weaker relative to crystalline Si wafers, contrary to previous results obtained for Fe/Si bilayers. Annealing of irradiated samples produces very similar interdiffusion and phase formation patterns above 400°C as in the non-irradiated Co/Si bilayers: the phase evolution follows the sequence Co2Si→CoSi→CoSi2. [Copyright &y& Elsevier]

Abstract: Ion implantation is a promising route for doping quartz with luminescent impurity atoms and nanoparticles at moderate fluences. The present work focuses on the comparison of epitaxy and cathodoluminescence (CL) after Ba, Ge, Na and Rb ion implantation as well as Rb/Ge double implantation in α-quartz, under the conditions of either dynamic or chemical epitaxy. In addition to the known intrinsic sub-bands in the CL spectra, due to the silica matrix or electron irradiation, we were able to line up several new blue or violet bands with the implanted ion species and follow their thermal behaviour. In the case of Na and Rb ions, complete chemical epitaxy has been achieved, but only rather weak CL output. For Ba ions, almost complete dynamic epitaxy and fairly high CL efficiency have been realized, but no epitaxy for Ge implantation. The case of dual Rb/Ge ion implantation appears as the most promising route to gain a high CL light output and full epitaxy. [Copyright &y& Elsevier]

Abstract: In the course of a systematic investigation of dynamic, chemical, and laser-induced solid phase epitaxy of α-quartz after ion implantation, we have studied epitaxy and cathodoluminescence emission after 250keV Cs-ion implantation and subsequent pulsed excimer laser treatment in air. Rutherford backscattering channelling analysis showed partial epitaxy for all the laser-irradiated samples; however, no full epitaxy was achieved. The optical properties of these samples were analyzed using cathodoluminescence spectroscopy, giving evidence of five emission bands at 2.42, 2.79, 3.25, 3.65, and 4.30eV photon energy. Their intensity relation to the laser power and retained Cs-ion fraction are discussed and the present results will be compared with those obtained after chemical and dynamic epitaxy of quartz after alkali-ion, Ge, and Ba implantation. [Copyright &y& Elsevier]

Solid phase epitaxial regrowth of α-quartz amorphized by ion implantation of dopants appears to be an attractive method for processing this optoelectronically important material. In an attempt to optimize solid phase epitaxy of α-quartz, we have studied the case of 50 keV 23Na ion implantation and annealing in an 18O atmosphere at 500–850 °C. The damage profiles were monitored by means of Rutherford backscattering-channeling, while the out-diffusion of the implanted 23Na and the 16O⇔18O exchange in the near-surface layers were investigated using the time-of-flight Elastic Recoil Detection analysis technique. As in the case of Cs-irradiated quartz, full epitaxial recrystallization was observed to occur for Na-irradiated quartz, however, at the lower temperature of approximately 650 °C (vs. 875 °C for Cs). Based on these observations, Na appears to offer a good compromise between a low recrystallization temperature (required to avoid oxidation of the dopants) and full recrystallization of the matrix. [Copyright &y& Elsevier]