30.08.2010

Catalyst Characterization: TEM vs. STEM

In (HR)TEM images of catalysts, it is often difficult to recognize metal nanoparticles with a diameter around 1 nm or below on strongly scattering crystalline oxides. For such systems, the combination of information obtained with an aberration-corrected STEM microscope equipped with BF, DF and secondary electron detectors provides a superior means to detect the nanoparticles, as demonstrated here for Pt particles on cerium oxide. more23.06.2010

Single Carbon Atom Chains

80kV- High Resolution Transmission Electron Microscopy (HRTEM) characterization of micromechanically cleaved graphene shows in real- time atomically resolved dynamics of the carbon atoms in graphene constrictions. During electron irradiation, processes of hole formation generate graphene constrictions and eventually lead to stable single carbon atom chains. Carbon chains also occur between carbonaceous adsorbates and looping along graphene edges. more19.04.2010

Formation of α-Manganese Dioxide Nanotubes

Hydrothermal decomposition of KMnO4 in the acidic environment in the presence of Fe3+(aq) ions leads to the formation of α-MnO2 nanotubes. The morphology evolution from the sponge-like spheres to the nanotubes as a function of reaction time was imaged by FE-SEM and TEM. The presence of iron in nanotubes was unambiguously confirmed by STEM-EELS measurement across the nanotube diameter.

Introduction
more04.11.2009

Fluorapatite-Gelatine Nanocomposites

Fluorapatite-gelatine nanocomposites serve as model system for mineralization steps of teeth and bone. The biomimetic composites show a hierarchical structural shape development starting from a hexagonal prismatic seed via dumbbell states and ending up with slightly notched spheres. This complex morphogenesis is caused by protein fibrils which are integrated into the nanocomposite superstructure. As evidenced by electron holography an intrinsic electric dipole field is generated by parallel alignment of nanocomposite subunits. more04.11.2009

HAADF and EELS Study of ULK Dielectrics

The ITRS requires the integration of dielectric materials with effective dielectric constant (k) lower than 2.8. This is achieved using porous SiOCH. Unfortunately during integration in the devices, damages are introduced in the low-k layer by CMP. The impact of these damages on the microstructure and the electronic properties are studied using HAADF imaging and Valence Electron Energy Loss Spectroscopy in TEM environment. Results are compared to low-k capped with an etch stop layer.
more04.11.2009

Fuel Cell Testing

Fuel cells are expected to play a major role in the future energy supply, especially polymer electrolyte membrane fuel cells could become an integral part in future cars. Reduction of degradation of fuel cell performance while keeping fuel cell cost under control is the key for an introduction into mass markets.
more04.11.2009

Clinical Electron Microscopy

The high resolution and sensitivity of electron microscopy is a valuable ancillary tool or gold standard in pathological diagnosis. The conventional sample turnaround time for processing in the lab can be significantly reduced from days to hours by the microwave technology. Microwave-assisted tissue processing, in combination with digital image acquisition, enables a "same-day" diagnosis in urgent clinical cases. Ultrastructural telepathology allows instant and live second opinion retrieval from a remote expert worldwide.

Introduction
more03.11.2009

Low Voltage Scanning Electron Microscopy

The development of instrumentation for microscopy has advanced enormously in recent years and one of the critical advancements has been the development of low voltage scanning electron microscopy (LVSEM) that allows high-resolution imaging of delicate biological structures with minimal coating requirements. LVSEM provides resolution at levels that previously could only be achieved with transmission electron microscopy (TEM). more