Silicon interface passivation studied by modulated surface photovoltage spectroscopy. - In: Peruvian Workshop on Solar Energy 2020 (JOPES 2020), 25-26 June 2020, Lima, Peru, (2021), 012003, S. 1-7
We demonstrate that the modulated surface photovoltage spectroscopy (modulated SPS) technique can be applied to investigate interface states in the bandgap, i.e. interface passivation, of crystalline silicon coated with a downshift layer such as hydrogenated aluminum nitride with embedded terbium ions by suppressing straylight with a cut-off filter. Different hydrogen contents influence the surface photovoltage spectra at photon energies below the bandgap of crystalline silicon. Modulated SPS reveals that at higher hydrogen content there is a lower signal and, thus, a lower density of surface defect states. Our experiments show that modulated SPS can become a powerful tool for characterizing defect states at interfaces which cannot be easily studied by other methods.
https://doi.org/10.1088/1742-6596/1841/1/012003
Nanopositioning and -fabrication using the Nano Fabrication Machine with a positioning range up to Ø 100 mm. - In: Novel Patterning Technologies 2021, (2021), S. 1161016-1-1161016-10
This paper focuses on a new Nano Fabrication Machine 100 (NFM-100) with a working range up to 100 mm in diameter and its integrated tip-based system, which can be used as an Atomic Force Microscope (AFM) as well as for Field-Emission-Scanning-Probe-Lithography (FESPL). The combination of both systems offers the possibility to fabricate and analyze micro- and nanostructures with high resolution and precision down to a single nanometer over a large area in one single configuration without tool or sensor change. After the description of the basic machine structure of the NFM-100, the demonstration of long range and large area AFM scans in combination with the NFM-100 will be shown. Additionally, the basic functionality of the FESPL manufacturing process is presented.
https://doi.org/10.1117/12.2583703
Conceptual design of a microscale balance based on force compensation. - In: Microactuators, microsensors and micromechanisms, (2021), S. 103-114
Macroscopic electromagnetic force compensation (EMFC) balances are well established but were not yet demonstrated within microsystems. Hence, in this paper, the concept and the design of a micro fabricated force compensation balance is presented. The implemented concentrated compliance mechanism in form of flexure hinges enables motion with high precision, which is combined with a force compensation mechanism. The concept of force compensation promises a high measurement range, which is expected to be up to 0.5 mN, while still enabling a high resolution of less than 8 nN. The developed dynamic model of the miniaturized balance is used for the design of a PID-controller strategy. Here, continuous and time-discrete controller approaches are compared. The time-discrete controller with realistic delay times, leads to an accuracy of the controller, which is better than the expected accuracy of the integrated capacitive position sensor.
https://doi.org/10.1007/978-3-030-61652-6_9
An electrothermally actuated membrane as oscillating pinhole for the high-frequent modulation of light. - In: DGaO-Proceedings, ISSN 1614-8436, Bd. 121 (2020), B37, insges. 2 S.
We present theory, processing steps and first results for a thermally actuated Aluminiumnitride-Platinum membrane with a resonant frequency of the first mode at around 100 kHz and resonant displacements at its center of around 30 µm. The radial-symmetric membrane is broadband opaque for wavelengths from visual light and beyond. An exception is a small pinhole of various diameters below 3 µm in its center. Through thermally induced asymmetric stress inside the multilayer, the clamped membrane bends out. The pinhole in its center will be displaced parallel to the optical axis.The intended use for such a membrane is to replace the traditional confocal pinhole in the detection path of a microscope. Applying a stable known resonant modulation on an acquired signal enables a lock-in principle for a differential confocal depth sensing as shown in [1]. The advantage over the employed tunable acoustic gradient lens (TAG lens) there, is the reduced size, the simplicity of the arrangement and constant illumination properties on the sample.
https://nbn-resolving.org/urn:nbn:de:0287-2020-B037-6
Additive manufactured injection moulds with optical quality surfaces. - In: Proceedings of the 20th International Conference of the European Society for Precision Engineering and Nanotechnology, (2020), S. 147-150
Self-aligning ruthenium interconnects. - In: 2020 IEEE International Interconnect Technology Conference (IITC), (2020), S. 82-84
This contribution shows self-aligning ruthenium interconnects. The underlying process is gas phase electrodeposition, which allows metallic particles to be deposited locally. This is performed with an adjustable airgap between the insulator and the deposited metallic structure. The size of the enclosed airgap can be adjusted directly. The deposition power has a direct influence on the growth rate and the morphology of the structure. With increasing deposition power, the resulting self-aligning nano-bridge becomes more compact.
https://doi.org/10.1109/IITC47697.2020.9515654
Chromium electroplating from Cr(III) in deep eutectic solvents. - In: Meeting abstracts, ISSN 2151-2043, Bd. MA2020-02 (2020), 59, 2908
https://doi.org/10.1149/MA2020-02592908mtgabs
Electrochemical nucleation of silicon in ionic liquid-based electrolytes. - In: Meeting abstracts, ISSN 2151-2043, Bd. MA2020-01 (2020), 19, 1181
https://doi.org/10.1149/MA2020-01191181mtgabs
Electrodeposition of cuprous oxide on a free-standing porous Cu framework for photoelectrochemical water splitting. - In: Meeting abstracts, ISSN 2151-2043, Bd. MA2020-02 (2020), 15, 1425
https://doi.org/10.1149/MA2020-02151425mtgabs
Advances in epitaxial GaInP/GaAs/Si triple junction solar cells. - In: 2020 47th IEEE Photovoltaic Specialists Conference (PVSC), (2020), S. 0194-0196
https://doi.org/10.1109/PVSC45281.2020.9300594