Publikationen


Suche nach „[Jonas] [Weber]“ hat 5 Publikationen gefunden
Suchergebnis als PDF
    NachhaltigF: Elektrotechnik und Medientechnik

    Zeitschriftenartikel

    Christoph Metzke, Fabian Kühnel, Jonas Weber, Günther Benstetter

    Scanning Thermal Microscopy of Ultrathin Films: Numerical Studies Regarding Cantilever Displacement, Thermal Contact Areas, Heat Fluxes, and Heat Distribution

    Nanomaterials, vol. 11, no. 2

    2021

    DOI: 10.3390/nano11020491

    Abstract anzeigen

    New micro- and nanoscale devices require electrically isolating materials with specific thermal properties. One option to characterize these thermal properties is the atomic force microscopy (AFM)-based scanning thermal microscopy (SThM) technique. It enables qualitative mapping of local thermal conductivities of ultrathin films. To fully understand and correctly interpret the results of practical SThM measurements, it is essential to have detailed knowledge about the heat transfer process between the probe and the sample. However, little can be found in the literature so far. Therefore, this work focuses on theoretical SThM studies of ultrathin films with anisotropic thermal properties such as hexagonal boron nitride (h-BN) and compares the results with a bulk silicon (Si) sample. Energy fluxes from the probe to the sample between 0.6 µW and 126.8 µW are found for different cases with a tip radius of approximately 300 nm. A present thermal interface resistance (TIR) between bulk Si and ultrathin h-BN on top can fully suppress a further heat penetration. The time until heat propagation within the sample is stationary is found to be below 1 µs, which may justify higher tip velocities in practical SThM investigations of up to 20 µms−1. It is also demonstrated that there is almost no influence of convection and radiation, whereas a possible TIR between probe and sample must be considered.

    NachhaltigF: Elektrotechnik und MedientechnikI: IQMA

    Zeitschriftenartikel

    Christoph Metzke, Werner Frammelsberger, Jonas Weber, Fabian Kühnel, K. Zhu, M. Lanza, Günther Benstetter

    On the Limits of Scanning Thermal Microscopy of Ultrathin Films

    Materials, vol. 13, no. 3

    2020

    DOI: 10.3390/ma13030518

    Abstract anzeigen

    Heat transfer processes in micro- and nanoscale devices have become more and more important during the last decades. Scanning thermal microscopy (SThM) is an atomic force microscopy (AFM) based method for analyzing local thermal conductivities of layers with thicknesses in the range of several nm to µm. In this work, we investigate ultrathin films of hexagonal boron nitride (h-BN), copper iodide in zincblende structure (γ-CuI) and some test sample structures fabricated of silicon (Si) and silicon dioxide (SiO2) using SThM. Specifically, we analyze and discuss the influence of the sample topography, the touching angle between probe tip and sample, and the probe tip temperature on the acquired results. In essence, our findings indicate that SThM measurements include artefacts that are not associated with the thermal properties of the film under investigation. We discuss possible ways of influence, as well as the magnitudes involved. Furthermore, we suggest necessary measuring conditions that make qualitative SThM measurements of ultrathin films of h-BN with thicknesses at or below 23 nm possible.

    NachhaltigF: Elektrotechnik und MedientechnikI: IQMA

    Vortrag

    Christoph Metzke, Günther Benstetter, Werner Frammelsberger, Jonas Weber, Fabian Kühnel

    Temperature dependent investigation of hexagonal boron nitride films using scanning thermal microscopy

    Poster presentation

    6th Nano Today Conference 2019, Lisbon, Portugal

    2019

    NachhaltigF: Elektrotechnik und MedientechnikF: Maschinenbau und MechatronikI: IQMA

    Zeitschriftenartikel

    L. Jiang, Jonas Weber, F. Puglisi, P. Pavan, L. Larcher, Werner Frammelsberger, Günther Benstetter, M. Lanza

    Understanding Current Instabilities in Conductive Atomic Force Microscopy

    Materials, vol. 12, no. 3

    2019

    DOI: 10.3390/ma12030459

    Abstract anzeigen

    Conductive atomic force microscopy (CAFM) is one of the most powerful techniques in studying the electrical properties of various materials at the nanoscale. However, understanding current fluctuations within one study (due to degradation of the probe tips) and from one study to another (due to the use of probe tips with different characteristics), are still two major problems that may drive CAFM researchers to extract wrong conclusions. In this manuscript, these two issues are statistically analyzed by collecting experimental CAFM data and processing them using two different computational models. Our study indicates that: (i) before their complete degradation, CAFM tips show a stable state with degraded conductance, which is difficult to detect and it requires CAFM tip conductivity characterization before and after the CAFM experiments; and (ii) CAFM tips with low spring constants may unavoidably lead to the presence of a ~1.2 nm thick water film at the tip/sample junction, even if the maximum contact force allowed by the setup is applied. These two phenomena can easily drive CAFM users to overestimate the properties of the samples under test (e.g., oxide thickness). Our study can help researchers to better understand the current shifts that were observed during their CAFM experiments, as well as which probe tip to use and how it degrades. Ultimately, this work may contribute to enhancing the reliability of CAFM investigations.

    NachhaltigF: Elektrotechnik und Medientechnik

    Vortrag

    Günther Benstetter, Christoph Metzke, Jonas Weber

    Recent Trends in Characterization of Nanoelectronic Materials and Devices with Scanning Probe Microscopy

    Invited Talk

    NanoScientific Symposium China - Scanning Probe Microscopy (SPM), Virtual Conference