S und N bleiben hängen: Metall‐organische Gerüstverbindungen (MOFs) können Treibstoffe von stickstoff‐ und schwefelhaltigen Verunreinigungen befreien (siehe Bild; ppmw=„parts per million“ nach Gewicht). Die Trennwirkung beruht auf Lewis‐sauren Metallzentren in den MOFs.

We report on the lattice location of Pr in thin film, single-crystalline hexagonal GaN using the emission channeling technique. The angular distribution of β − particles emitted by the radioactive isotope 143 Pr was monitored by a position-sensitive electron detector following 60 keV room temperature implantation of the precursor isotope 143 Cs at a dose of 1×10 13 cm −2 and annealing up to 900°C. Our experiments provide direct evidence that Pr is thermally stable at substitutional Ga sites.

We provide the first systematic characterization of the structural and photoluminescence properties of optically active centers fabricated upon implantation of 30–100 keV Mg+ ions in synthetic diamond. The structural configurations of Mg-related defects were studied by the electron emission channeling technique for short-lived, radioactive 27Mg implantations at the CERN-ISOLDE facility, performed both at room temperature and 800 °C, which allowed the identification of a major fraction of Mg atoms (∼30 to 42%) in sites which are compatible with the split-vacancy structure of the MgV complex. A smaller fraction of Mg atoms (∼13 to 17%) was found on substitutional sites. The photoluminescence emission was investigated both at the ensemble and individual defect level in the 5–300 K temperature range, offering a detailed picture of the MgV-related emission properties and revealing the occurrence of previously unreported spectral features. The optical excitability of the MgV center was also studied as a function of the optical excitation wavelength to identify the optimal conditions for photostable and intense emission. The results are discussed in the context of the preliminary experimental data and the theoretical models available in the literature, with appealing perspectives for the utilization of the tunable properties of the MgV center for quantum information processing applications.

In advanced multi-level metallization schemes, the application of copper as interconnect metal requires the prevention of Cu diffusion into the active area and into interlevel dielectrics by total encapsulation of Cu with barrier films. Critical requirements for diffusion barriers are very small thicknesses, low resistivity, low deposition temperature and conformality on high aspect ratio trenches and vias. For this application, we have studied TiN films deposited by atomic layer chemical vapour deposition (ALCVD) at 400°C and 350°C. This paper discusses the ALCVD TiN films properties and compares them to the properties of TiN deposited by ionized physical vapour deposition (I-PVD).The ALCVD TiN deposited at 400°C exhibits a resistivity comparable to I-PVD TiN resistivity. However, the ALCVD films deposited at 350°C show higher resistivity. The Cl residue in ALCVD films is 1.5% at 400°C and 3% at 350°C. The microstructure is fine-grained. A very high level of conformality on trenches characterizes the ALCVD TiN films. We believe this property gives a clear advantage over the sputtered I-PVD TiN since its coverage in high aspect ratio trenches and vias is expected to be limited for the future devices interconnection scheme.

Commercial light emitting devices (LEDs) containing InGaN layers offer unrivalled performance in the violet (∼400 nm), blue (∼450 nm) and green (∼520 nm) spectral regions. Nichia Chemicals Company has also produced amber InGaN LEDs with peak output near 590 nm. Here, we predict, on purely theoretical grounds, a surprisingly high limiting value of 1020 nm (peak) for InGaN intrinsic emission. We partly confirm this prediction by spectroscopic measurements of samples with photoluminescence (PL) peaks between 370 nm and 980 nm. In addition, we have measured the indium content of a range of light-emitting layers, using Rutherford Backscattering Spectrometry (RBS), Extended X-Ray Absorption Fine Structure (EXAFS) and Energy Dispersive X-Ray Analysis (EDX). The PL peak energy is found to depend linearly on the indium fraction: violet-emitting layers have an indium content of ∼8%, blue layers ∼16% and green layers ∼25%. A linear extrapolation to the limit set by the Stokes' shift prediction, mentioned earlier, yields a limiting indium concentration of only ∼52%. The profound impact of these results on future extensions of nitride technology and current theoretical models of InGaN is briefly discussed.