Christian Patzig - Academia.edu (original) (raw)

Papers by Christian Patzig

MRS Proceedings, 2009

ABSTRACT Amorphous Si/SiOx multi-layered films and nanostructures were deposited on Si substrates... more ABSTRACT Amorphous Si/SiOx multi-layered films and nanostructures were deposited on Si substrates by the glancing angle deposition technique using Ar ion beam sputtering of a Si sputter target in an intermittent oxygen atmosphere at room temperature. The chemical composition of the samples was characterized by time-of-flight secondary ion mass spectrometry, as well as - for quantifying these first results - by elastic recoil detection analysis using a 200 MeV Au ion beam. The latter method was found to lead to a significant alteration of the sample morphology, resulting in the formation of complex nanometric structures within the layer stacks. In order to investigate these swift heavy ion irradiation induced effects in more detail, a series of experiments was conducted to determine the dominating influences. For this purpose, specific glancing angle deposited multilayered films and nanostructures were irradiated to constant ion fluence with the same 200 MeV Au ion beam at different incidence angles. Scanning electron microscopy of the stacks before and after swift Au ion irradiation revealed considerable changes in film morphology and density as a function of the ion incidence angle, such as an increased porosity of the silicon layers, accompanied by a layer swelling. In contrast, the SiOx layers did not show such effects, but exhibited clearly visible swift heavy ion tracks. The observed effects became stronger with decreasing ion incidence angle.

2008 2nd Ieee International Nanoelectronics Conference, Vols 1-3, 2008

ABSTRACT

Nanostructured Thin Films, 2008

When an electromagnetic wave interacts with a nano structured metallic surface or a nanoparticle,... more When an electromagnetic wave interacts with a nano structured metallic surface or a nanoparticle, the electromagnetic fields near the surface are greatly enhanced by factors up to 1000. This phenomenon is due to two processes: (i) the 'lightning rod' effect, conventionally described as the crowding of the electric field lines at a sharp metallic tip and (ii) the excitation of

Nanostructured Thin Films Iv, 2011

Nano-sculptured thin films (STF) are prepared by the glancing angle deposition technique and take... more Nano-sculptured thin films (STF) are prepared by the glancing angle deposition technique and take different forms of nano columnar structures. Varieties of STFs are investigated to find the optimum structure for biosensing based on the surface enhanced fluourescence (SEF). The highest amplification of fluorescent signal is found for Ag based STFs on fused silica giving an enhancement factor of x23°, where h=400nm, d=75nm, Ã¡=23o relative to Ag dense film using fluorescent dye Rhodamine 123. Based on this, a demonstration of monitoring of antibodies and even confirmation of successful immobilization of the receptors presented. Bound antibody to the thiol self assembly monolayer on sample surface is then quantified by means of the fluorescent signal. Upon excitation of the fluorophore by Hg source light, a CCD camera with a controlled exposure time detects the pattern of fluorescent antibody/E-coli bacteria colonies on the STF surface. A fiber optic holder attached to the microscope allowed quantitative measurement of the fluorescence spectrum on a microspot.

Microsystem Technologies, 2014

ABSTRACT Two sapphire substrates are tightly bonded through a fresnoite-glass thin film, by irrad... more ABSTRACT Two sapphire substrates are tightly bonded through a fresnoite-glass thin film, by irradiation with a 1,064 nm nanosecond laser. The composition of the glass solder at the bond interface changes, due to incorporation of Al from the upper substrate. The oxidic solder remains amorphous after laser irradiation, but after annealing (850 °C for 1 h) crystalline structures are observed in different morphologies, which are attributed not only to fresnoite, but also to Ba–Ti–Al–O phases, which lead to a strong luminescence of the laser irradiated region under UV excitation.

physica status solidi (b), 2010

Photonics and Nanostructures - Fundamentals and Applications, 2009

Surface plasmon (SP) waves on the interface of a dielectric (such as water) and a metallic column... more Surface plasmon (SP) waves on the interface of a dielectric (such as water) and a metallic columnar thin film (CTF) of porosity as high as 0.55 were experimentally and theoretically investigated. The CTFs were made of Al, Au, Ag, or Cr. As the porosity increases, the SP resonance (SPR) dip was found to widen, shift to higher wave numbers, and

Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 2010

ABSTRACT When Ag sculptured thin films were grown with glancing angle deposition by ion beam sput... more ABSTRACT When Ag sculptured thin films were grown with glancing angle deposition by ion beam sputtering at either room temperature or elevated substrate temperatures T{sub S}, a large morphological difference was observed. The incident particle flux reached the silicon substrate at a glancing angle {beta}{>=}80 deg. as measured to the substrate normal. A slit aperture was used in order to reduce the particle beam divergence. At room temperature, columnar structures were formed, irrespective of the presence of the slit aperture. At elevated temperatures (573 and 623 K) and collimated particle flux in the presence of the slit aperture, however, enhanced surface diffusion causes the growth of crystalline nanorod- and nanowirelike structures. In the absence of the slit aperture, the flux beam divergence is higher, resulting in island- and mountainlike crystalline structures. The density of the nanorods and nanowires was observed to be higher on the planar Si substrates in comparison to honeycomblike prepatterned substrates with different pattern periods. On the patterned substrates, the nanorods are not necessarily found to be evolving on the seed points but can rather be also observed in-between the artificial seeds. The glancing angle deposited films at high temperatures were observed to be polycrystalline, where the (111) crystal orientation of the film is dominant, while the presence of the less intense (200) reflection was noticed from the x-ray diffraction measurements. In contrast, compact thin films deposited with {beta}{approx_equal}0 deg. at high temperatures were found to be epitaxial with (200) orientation.

Journal of Physics D: Applied Physics, 2009

Five-armed Si nanospring coatings were grown by glancing angle deposition on Si(1 1 1) substrates... more Five-armed Si nanospring coatings were grown by glancing angle deposition on Si(1 1 1) substrates pre-patterned with sub-micrometre sized silica and polystyrene spheres. The stiffness of the individual Si nanosprings was determined by atomic force microscope based force-distance spectroscopy. These Si nanospring coatings were irradiated with 1.2 MeV Ar+8 ions at liquid nitrogen temperature at different ion fluences varying from

Journal of Physics D: Applied Physics, 2014

Fresnoite Ba 2 TiSi 2 O 8 (BTS) thin films were grown and crystallized in situ using pulsed laser... more Fresnoite Ba 2 TiSi 2 O 8 (BTS) thin films were grown and crystallized in situ using pulsed laser deposition (PLD) with CO 2 laser direct heating of the a-plane sapphire (1 1 0) substrates up to 1250 • C. Starting with 775 • C growth temperature, (0 0 1)-and (1 1 0)-textured BTS and BaTiO 3 phases, respectively, could be assigned in the films, and the typical fern-like BTS crystallization patterns appear. For higher process temperatures of 1100 to 1250 • C, atomically smooth, terraced surface of the films was found, accompanied by crystalline high-temperature phases of Ba-Ti-Si oxides. HAADF micrographs taken in both scanning transmission electron microscopy and energy-dispersive x-ray spectrometry mode show details of morphology and elemental distribution inside the films and at the interface.

Journal of Nanoscience and Nanotechnology, 2010

Experimental studies were undertaken to determine mechanical stiffness of Si chevron nanostructur... more Experimental studies were undertaken to determine mechanical stiffness of Si chevron nanostructures grown by glancing angle deposition. Atomic force microscope based force-distance spectroscopy was performed on two types of chevron structures. The average stiffness of four-armed chevrons was found to be 381 +/- 16 Nm(-1), while that of five-armed chevrons was determined to be 375 +/- 23 Nm(-1). Simulations using finite element modeling were carried out to understand the mechanical characteristics of chevrons. For the nanostructures investigated in the present study, the simulation results indicate that while five-armed chevrons behave as springs, the four-armed chevrons act as cantilevers. It is shown that the position of loading point, physical dimensions and the geometry of the chevron control the overall mechanical response of chevron structures when subjected to an external load. It is proposed that by controlling the deposition parameters in glancing angle deposition, the topography of the structures and hence the position of loading points can be manipulated to generate a desirable mechanical response.

Journal of Applied Physics, 2008

Ordered arrays of Si nanorods and nanospirals have been produced by ion beam sputter glancing ang... more Ordered arrays of Si nanorods and nanospirals have been produced by ion beam sputter glancing angle deposition of Si on rotating substrates. The substrates were prepatterned with honeycomb and hexagonal-closed-packed arranged Au dots obtained by nanosphere lithography. The effects of template type, substrate rotational speed, height of the artificial Au seeds, and deposition angle of the incident flux on the growth of the Si nanostructures is examined. Especially for the deposition of Si on honeycomb templates at different deposition angles, it is shown that the structure of the growing film changes drastically. A continuous film with honeycomblike arranged hillocks on top is deposited at normal incidence. With increased , the structure shifts to almost dense films with a mesh of hexagonally arranged pores ͑ = 70°͒. Finally, separated rodlike structures with triangular cross section are obtained under glancing angle conditions ͑ = 85°͒. In addition, the structural evolution of the glancing angle deposited Si films is compared with oblique angle deposition three-dimensional Monte Carlo simulations. Furthermore, the effects of surface diffusion on the growth of spiral Si nanostructures on nontemplated substrates in experiment and simulation are compared and discussed.

Journal of Applied Physics, 2010

In this study, the compressive strength of individual Si nanosprings grown by glancing angle depo... more In this study, the compressive strength of individual Si nanosprings grown by glancing angle deposition was determined by atomic force microscope based force-distance spectroscopy. Different irradiation conditions were employed to separately investigate the role of inelastic electronic excitations and elastic nuclear stopping on the stiffness of Si nanosprings. This was achieved by using different ion beams at various energies such

Journal of Applied Physics, 2011

We report on the experimental and theoretical investigation of the magnetization reversal in magn... more We report on the experimental and theoretical investigation of the magnetization reversal in magnetic nanotubes that have been synthesized by a combination of glancing angle and atomic layer deposition. Using superconducting quantum interference device magnetometry the angular dependence of the coercive fields is determined and reveals a nonmonotonic behavior. Analytical calculations predict the crossover between two magnetization reversal modes, namely, the movement of different types of domain boundaries (vortex wall and transverse wall). This transition, already known in the geometrical dependences of the magnetization reversal in various nanotubes, is found within one type of tube in the angular dependence and is experimentally confirmed in this work.

CrystEngComm, 2013

Rare-earth (RE) doped transparent glass-ceramics are presented as very promising materials for op... more Rare-earth (RE) doped transparent glass-ceramics are presented as very promising materials for optical applications. In this work, Transmission Electron Microscopy techniques have been used to structurally characterize a glass of composition 55SiO 2 -20Al 2 O 3 -15Na 2 O-10LaF 3 (mol%), doped with 1 mol% Tm 2 O 3 , and the corresponding glass-ceramic. The proposed crystallization mechanism for this glass has been modified from the results obtained through advanced STEM/EDXS techniques. The parent glass contains phase separated regions mainly enriched in F and La and also in Al, Si and Tm. After annealing, 10-20 nm LaF 3 nano-crystals are formed from these phase separated droplets. The partial incorporation of the doping Tm 3+ ions into the LaF 3 nano-crystals has been verified and the interphase crystal/glassy matrix has been more precisely characterized through EDXS. An Al enriched layer is formed around the crystals followed by a Si enriched shell, which greatly increase the viscosity in the periphery of the crystals, inhibiting further crystal growth and thus, keeping the nano size of the crystals.

Crystal Growth & Design, 2012

Glasses are usually synthesized by quenching a melt rapidly enough to avoid crystallization. Nano... more Glasses are usually synthesized by quenching a melt rapidly enough to avoid crystallization. Nanocrystalline materials can subsequently be derived from glasses by controlled crystallization with applying a tailored heat treatment. Upon the latter, nucleation agents are widely used to adjust the desired nanostructures. Nano glass-ceramics often possess intriguing properties. For example, they can be ultratransparent; that is, they hardly scatter light or possess thermal expansion coefficients very close to zero. Such properties have a high potential for future applications in optical devices. In this paper, the role of zirconia and titania used as nucleation agents in a lithia aluminosilicate glass is studied on the nanoscale using cutting edge analytical and imaging techniques performed using the transmission electron microscope. Precipitation of ZrTiO 4 nanocrystals [Bhattacharyya, S., et al. Nano Lett. 2009, 9, 2493 was found earlier to be accompanied by the formation of a circumjacent diffusion barrier consisting of alumina. In addition to this, here we study the temporal evolution of the alumina barrier and the size distributions of ZrTiO 4 nanocrystals and lithia aluminosilicate high-quartz solid solution crystals promoted by the nucleation agent. In the light of these findings, the theory of self-limited growth is refined.

Applied Surface Science, 2012

ABSTRACT Epitaxial Ag films were grown on native oxide covered Si(1 0 0) substrates by an ion bea... more ABSTRACT Epitaxial Ag films were grown on native oxide covered Si(1 0 0) substrates by an ion beam sputter deposition process at elevated deposition temperatures. At RT, films were observed to be non-epitaxial but with preferred (1 1 1) orientation. However, elevated substrate temperatures and under highly energetic sputter deposition process assist the growth of Ag films, that exhibit an epitaxial relationship with the underlying Si(1 0 0) substrates. With increasing deposition temperature an increase in the crystalline quality was observed with a narrowing mosaic distribution of crystallites and a decrease in the fraction of 1st order twins. The lowest epitaxial growth temperature was observed to be as low as 100 °C.

Applied Physics Letters, 2009

ABSTRACT An approach to deposit sculptured nanostructures with arbitrary interstructure spacing i... more ABSTRACT An approach to deposit sculptured nanostructures with arbitrary interstructure spacing is presented. Based on a combination of glancing angle deposition with a preceding two-step electron beam lithography substrate patterning, the concept allows the deposition of nanostructures on artificial seeds at any predetermined place on the substrate. Due to the glancing angle deposition principle, with the help of an appropriate substrate rotation during deposition, those structures can additionally be shaped into nearly arbitrary morphologies. To demonstrate the feasibility of the proposed method, separated sculptured nanostructures of silicon with interstructure spacings of (10–20) μm were assembled.