@article{KrenzerHanischBlicharskiSchneideretal., author = {Krenzer, Boris and Hanisch-Blicharski, Anja and Schneider, Paul and Payer, Thomas and M{\"o}llenbeck, Simone and Osmani, O. and Kammler, Martin and Meyer, R. and Horn-von Hoegen, Michael}, title = {Phonon confinement effects in ultrathin epitaxial bismuth films on silicon studied by time-resolved electron diffraction}, series = {Physical Review B}, volume = {80}, journal = {Physical Review B}, number = {2}, publisher = {APS}, doi = {10.1103/PhysRevB.80.024307}, abstract = {The transient temperature evolution of ultrathin bismuth films, epitaxially grown on a silicon single crystal, upon femtosecond laser excitation is studied by time-resolved electron diffraction. The exponential decay of the film temperature is explained by phonon reflection at the interface, which results in a strongly reduced thermal conduction in the cross plane of the layered system. The thermal boundary conductance is found to be as low as 1273 W/(K cm2). Model calculations, including phonon confinement effects, explain the linear relationship between the observed film-temperature decay constant and the film thickness. Even for 2.5 nm thin films the phonon transmission probability across the interface is given by bulk properties. Our simulations show that phonon confinement effects are negligible for bismuth-film thicknesses larger than 1 nm.}, language = {en} } @article{KleinNabbefeldHattabetal., author = {Klein, C. and Nabbefeld, T. and Hattab, H. and Meyer, D. and Jnawali, G. and Kammler, Martin and Meyer zu Heringdorf, Frank-Joachim and Golla-Franz, A. and M{\"u}ller, B. H. and Schmidt, Thomas and Henzler, M. and Horn-von Hoegen, Michael}, title = {Lost in reciprocal space? Determination of the scattering condition in spot profile analysis low-energy electron diffraction}, series = {Review of scientific instruments}, volume = {82}, journal = {Review of scientific instruments}, number = {3}, publisher = {American Institute of Physics}, doi = {10.1063/1.3554305}, abstract = {The precise knowledge of the diffraction condition, i.e., the angle of incidence and electron energy, is crucial for the study of surface morphology through spot profile analysis low-energy electron diffraction (LEED). We demonstrate four different procedures to determine the diffraction condition: employing the distortion of the LEED pattern under large angles of incidence, the layer-by-layer growth oscillations during homoepitaxial growth, a G(S) analysis of a rough surface, and the intersection of facet rods with 3D Bragg conditions.}, language = {en} } @article{SchmidtKroegerClausenetal., author = {Schmidt, Thomas and Kr{\"o}ger, Roland and Clausen, T. and Falta, J. and Janzen, Andreas and Kammler, Martin and Kury, P. and Zahl, P. and Horn-von Hoegen, Michael}, title = {Surfactant-mediated epitaxy of Ge on Si(111): Beyond the surface}, series = {Applied Physics Letters}, volume = {86}, journal = {Applied Physics Letters}, number = {11}, publisher = {AIP}, doi = {10.1063/1.1882760}, abstract = {For a characterization of interface and "bulk" properties of Ge films grown on Si(111) by Sb surfactant-mediated epitaxy, grazing incidence x-ray diffraction and transmission electron microscopy have been used. The interface roughness, defect structure, and strain state have been investigated in dependence of film thickness and growth temperature. For all growth parameters, atomically smooth interfaces are observed. For thin Ge layers, about 75\% of the strain induced by the lattice mismatch is relaxed by misfit dislocations at the Ge/Si interface. Only a slight increase of the degree of relaxation is found for thicker films. At growth temperatures below about 600 °C, the formation of twins is observed, which can be avoided at higher temperatures.}, language = {en} } @article{FriggeWallKrenzeretal., author = {Frigge, Tim and Wall, S. and Krenzer, Boris and Wippermann, St. and Sanna, Simone and Klasing, Friedrich and Hanisch-Blicharski, Anja and Kammler, Martin and Schmidt, Wolf Gero and Horn-von Hoegen, Michael}, title = {Abstract - A Reply to the Comment by H. Shim et al.}, series = {Physical review letters}, volume = {111}, journal = {Physical review letters}, number = {14}, publisher = {American Physical Society}, doi = {10.1103/PhysRevLett.111.149602}, language = {en} } @article{CheeKammlerGrahametal., author = {Chee, See Wee and Kammler, Martin and Graham, Jeremy and Ross, Frances M. and Hull, Robert}, title = {Direct Imaging of Microstructural Changes in Si Induced by FIB-Patterning with Si ++ and Ga + Ions}, series = {Microscopy and Microanalysis}, volume = {17}, journal = {Microscopy and Microanalysis}, number = {S2}, publisher = {Cambridge University Press}, doi = {10.1017/S1431927611004156}, pages = {656 -- 657}, language = {en} } @article{WolfgrammAbbSampetal., author = {Wolfgramm, Alex and Abb, Valerius and Samp, Artur and Samp, Rafal and Hoffmann, Jens Christoph and M{\"u}ller, Rainer and Kammler, Martin}, title = {Structural and functional evolution of HKUST-1 nanoparticles induced by ball milling}, series = {Next Materials}, volume = {10}, journal = {Next Materials}, publisher = {Elsevier}, doi = {10.1016/j.nxmate.2025.101544}, pages = {7}, abstract = {In this study, the effect of post-synthetic ball milling on the structural and functional properties of as-synthesized nanoparticles of the copper-based metal-organic framework (MOF) HKUST-1 was investigated for the first time. Nanoparticles were synthesized using sodium formate as a capping agent. The crystalline particles were subjected to a controlled ball milling process, which induced significant structural changes. Powder X-ray diffraction (PXRD) revealed a reduction in crystallite size from 91 nm to 21 nm and the introduction of microstrain, partially disrupting the MOF's long-range crystalline order, as evidenced by peak broadening and the diminished intensity of high-angle reflections. Particle morphology pre- and post-milling was further studied with scanning electron microscopy (SEM) imaging, verifying a narrow particle size distribution of ± 22 nm after milling. Fourier-transform infrared spectroscopy (FTIR) indicated protonation of carboxylate groups in the larger pores of the framework, likely due to moisture incorporation during milling. Brunauer-Emmett-Teller (BET) surface area analysis showed a substantial decrease in specific surface area from 521 m²/g to 226 m²/g, suggesting a partial collapse of the porous framework. We discuss the applicability of ball milling as a versatile means of post-synthetic approach to reduce MOF particle sizes, a key element in the preparation of MOF-based thin films using inks or polymers.}, language = {en} }