TY - GEN A1 - Oleynik, Paul A1 - Berkmann, Fritz A1 - Reiter, Sebastian A1 - Schlipf, Jon A1 - Ratzke, Markus A1 - Yamamoto, Yuji A1 - Fischer, Inga Anita T1 - Strong Optical Coupling of Lattice Resonances in a Top-down Fabricated Hybrid Metal–Dielectric Al/Si/Ge Metasurface T2 - Nano Letters N2 - Optical metasurfaces enable the manipulation of the light–matter interaction in ultrathin layers. Compared with their metal or dielectric counterparts, hybrid metasurfaces resulting from the combination of dielectric and metallic nanostructures can offer increased possibilities for interactions between modes present in the system. Here, we investigate the interaction between lattice resonances in a hybrid metal–dielectric metasurface obtained from a single-step nanofabrication process. Finite-difference time domain simulations show the avoided crossing of the modes appearing in the wavelength-dependent absorptance inside the Ge upon variations in a selected geometry parameter as evidence for strong optical coupling. We find good agreement between the measured and simulated absorptance and reflectance spectra. Our metasurface design can be easily incorporated into a top-down optoelectronic device fabrication process with possible applications ranging from on-chip spectroscopy to sensing. KW - metamaterials KW - semiconductors KW - hybridization KW - optoelectronics Y1 - 2024 U6 - https://doi.org/10.1021/acs.nanolett.3c05050 SN - 1530-6984 SN - 1530-6992 VL - 24 IS - 10 SP - 3142 EP - 3149 ER - TY - GEN A1 - Nitsch, Paul-G. A1 - Ratzke, Markus A1 - Pozarowska, Emilia A1 - Flege, Jan Ingo A1 - Alvarado Chavarin, Carlos A1 - Wenger, Christian A1 - Fischer, Inga Anita T1 - Deposition of reduced ceria thin films by reactive magnetron sputtering for the development of a resistive gas sensor T2 - Verhandlungen der DPG, Berlin 2024 N2 - The use of cerium oxide for hydrogen sensing is limited by the low electrical conductivity of layers deposited from a ceria target. To increase the electrical conductivity, partially reduced cerium oxide layers were obtained from a metallic cerium target by reactive magnetron sputtering. The proportions of the oxidation states Ce3+, present in reduced species, and Ce4+, present in fully oxidized species, were determined by ex-situ XPS. For electrical characterization, films were deposited on planarized tungsten finger electrodes. IV curves were measured over several days to investigate possible influences of oxygen and humidity on electrical conductivity. The morphological stability of the layers under ambient conditions was investigated by microscopical methods. The XPS results show a significant amount of Ce3+ in the layers. The electrical conductivity of as-grown samples is several orders of magnitude higher than that of samples grown from a ceria target. However, the conductivity decreases over time, indicating an oxidation of the layers. The surface morphology of the samples was found to be changing drastically within days, leading to partial delamination. KW - ceria KW - metalic cerium target KW - electrical conductivity KW - X-ray photoelectron spectroscopy (XPS) KW - oxidation states KW - morphology Y1 - 2024 UR - https://www.dpg-verhandlungen.de/year/2024/conference/berlin/part/ds/session/11/contribution/18 SN - 0420-0195 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - GEN A1 - Kosto, Yuliia A1 - Tschammer, Rudi A1 - Morales, Carlos A1 - Henkel, Karsten A1 - Flege, Jan Ingo A1 - Ratzke, Markus A1 - Fischer, Inga Anita A1 - Costina, Ioan A1 - Alvarado Chavarin, Carlos A1 - Wenger, Christian T1 - Rational design and development of room temperature hydrogen sensors compatible with CMOS technology: a necessary step for the coming renewable hydrogen economy T2 - Proceedings of iCampus Conference Cottbus 2024 N2 - The transition towards a new, renewable energy system based on green energy vectors, such as hydrogen, requires not only direct energy conversion and storage systems, but also the development of auxiliary components, such as highly sensitive hydrogen gas sensors integrated into mass devices that operate at ambient conditions. Despite the recent advances in nanostructured metal oxide thin films in terms of simple fabrication processes and compatibility with integrated circuits, high sensitivity, and short response/recovery times usually require the use of expensive noble metals or elevated tem-peratures (>250 ºC), which results in high power consumption and poor long-term stability. This article presents the first steps of the work on developing a novel resistive hydrogen gas sensor based on ultrathin cerium oxide films, compatible with complementary metal oxide semiconductor technology and capable of operating at room temperature. Here, we show a multidisciplinary bottom-up approach combining different work areas for the sensor development, such as sensor architecture, sensing mechanism and deposition strategy of the active layer, electrical contact design depending on the desired electrical output, and fast testing under controlled environments. KW - gas sensors KW - micro-structering KW - atomic layer deposition KW - sensor platform Y1 - 2024 SN - 978-3-910600-00-3 U6 - https://doi.org/10.5162/iCCC2024/P21 SP - 182 EP - 185 PB - AMA Service GmbH CY - Wunstorf ER - TY - GEN A1 - Becker, L. A1 - Storck, Peter A1 - Liu, Y. A1 - Schwalb, G. A1 - Schroeder, Thomas A1 - Fischer, Inga Anita A1 - Albrecht, M. T1 - Optimizing misfit dislocation glide kinetics for enhanced threading dislocation density reduction in Si1− xGex/Si (001) layers through dynamic growth rate control T2 - Journal of Applied Physics Y1 - 2024 U6 - https://doi.org/10.1063/5.0204318 SN - 0021-8979 SN - 1089-7550 VL - 135 IS - 20 SP - 10 ER - TY - GEN A1 - Berkmann, Fritz A1 - Povolni, Pavel A1 - Schwarz, Daniel A1 - Fischer, Inga Anita T1 - Influence of material and geometry parameters on resonance linewidths of plasmonic modes in gratings made from highly doped Ge1−xSnx T2 - Journal of Physics D: Applied Physics Y1 - 2024 U6 - https://doi.org/10.1088/1361-6463/ad67ea VL - 57 IS - 43 SP - 10 ER - TY - GEN A1 - Hayat, Ahsan A1 - Ratzke, Markus A1 - Alvarado Chavarin, Carlos A1 - Zöllner, Marvin Hartwig A1 - Corley-Wiciak, Agnieszka Anna A1 - Schubert, Markus Andreas A1 - Wenger, Christian A1 - Fischer, Inga Anita T1 - Structural and morphological properties of CeO2 films deposited by radio frequency magnetron sputtering for back-end-of-line integration T2 - Thin Solid Films Y1 - 2024 U6 - https://doi.org/10.1016/j.tsf.2024.140547 SN - 0040-6090 VL - 807 ER - TY - GEN A1 - Reiter, Sebastian A1 - Sengül, Akant A1 - Mai, Christian A1 - Spirito, Davide A1 - Wenger, Christian A1 - Fischer, Inga Anita T1 - On-chip refractive index sensors based on plasmonic TiN Nanohole Arrays T2 - 2024 IEEE Silicon Photonics Conference (SiPhotonics) Y1 - 2024 SN - 979-8-3503-9404-7 SN - 979-8-3503-9405-4 U6 - https://doi.org/10.1109/SiPhotonics60897.2024.10544048 SN - 1949-209X ER - TY - GEN A1 - Fischer, Inga Anita T1 - CMOS-compatible metasurfaces integrated with optoelectronic devices: tuning light-matter interaction at the nanoscale T2 - Technical Digest Series (Optica Publishing Group, 2024), paper SM2L.7 Y1 - 2024 SN - 978-1-957171-39-5 U6 - https://doi.org/10.1364/CLEO_SI.2024.SM2L.7 ER - TY - GEN A1 - Jose, Josmy A1 - Mai, Christian A1 - Wenger, Christian A1 - Fischer, Inga Anita T1 - Integration concept of plasmonic TiN nanohole arrays in a 200 mm BiCMOS Si technology for refractive index sensor applications T2 - iCCC2024 - iCampµs Cottbus Conference Y1 - 2024 U6 - https://doi.org/10.5162/iCCC2024/7.2 SP - 96 EP - 99 ER - TY - GEN A1 - Mai, Christian A1 - Peczek, Anna A1 - Kroh, Aleksandra A1 - Jose, Josmy A1 - Reiter, Sebastian A1 - Wenger, Christian A1 - Fischer, Inga Anita T1 - Towards a CMOS compatible refractive index sensor: cointegration of TiN nanohole arrays and Ge photodetectors in a 200 mm wafer silicon technology T2 - Optics Express N2 - In this work, we present the monolithic integration of a TiN nanohole array and a Ge photodetector towards a CMOS compatible fabrication of a refractive index sensor in a 200 mm wafer silicon technology. We developed a technology process that enables fabrication with high yields of around 90%. Ge photodetectors with a Ge layer thickness of 450 nm and an area of 1600 µm2 (40 µm x 40 µm) show dark current densities of around 129 mA/cm2 and responsivities of 0.114 A/W measured by top illumination (TE polarization; λ = 1310 nm; angle of incidence = 14 °) at a reverse bias of 1 V. Nanohole arrays were structured in a 150 nm thick TiN layer. They were integrated into the back end of line and placed spatially close to the Ge photodetectors. After the metallization, passivation, and pad opening, the nanohole arrays were released with the help of an amorphous silicon stop layer. A significant impact of the TiN nanohole arrays on the optical behavior of the photodetector could be proven on the wafer level. Photocurrent measurements by top illumination confirm a strong dependence of optical properties on the polarization of the incident light and the nanohole array design. We demonstrate very stable photocurrents on the wafer level with a standard deviation of σ < 6%. KW - plasmonics KW - sensor KW - nano hole array Y1 - 2024 U6 - https://doi.org/10.1364/OE.530081 SN - 1094-4087 VL - 32 IS - 17 SP - 29099 EP - 29111 PB - Optica Publishing Group ER - TY - GEN A1 - Berkmann, Fritz A1 - Steuer, Oliver A1 - Ganss, Fabian A1 - Prucnal, Slawomir A1 - Schwarz, Daniel A1 - Fischer, Inga Anita A1 - Schulze, Jörg T1 - Sharp MIR plasmonic modes in gratings made of heavily doped pulsed laser-melted Ge1-xSnx T2 - Optical Materials Express Y1 - 2023 U6 - https://doi.org/10.1364/OME.479637 SN - 2159-3930 VL - 13 IS - 3 SP - 752 EP - 763 ER - TY - GEN A1 - Weißhaupt, David A1 - Funk, Hannes S. A1 - Oehme, Michael A1 - Bloos, Dominik A1 - Berkmann, Fritz A1 - Seidel, Lukas A1 - Fischer, Inga Anita A1 - Schulze, Jörg T1 - High mobility Ge 2DHG based MODFETs for low-temperature applications T2 - Semiconductor Science and Technology Y1 - 2023 U6 - https://doi.org/10.1088/1361-6641/acb22f SN - 1361-6641 VL - 38 IS - 3 ER - TY - GEN A1 - Reiter, Sebastian A1 - Han, Weijia A1 - Mai, Christian A1 - Spirito, Davide A1 - Jose, Josmy A1 - Zöllner, Marvin Hartwig A1 - Fursenko, Oksana A1 - Schubert, Markus Andreas A1 - Stemmler, Ivo A1 - Wenger, Christian A1 - Fischer, Inga Anita T1 - Titanium Nitride Plasmonic Nanohole Arrays for CMOS-compatible integrated refractive index sensing: influence of layer thickness on optical properties T2 - Plasmonics Y1 - 2023 U6 - https://doi.org/10.1007/s11468-023-01810-3 SN - 1557-1963 SP - 1 EP - 13 ER - TY - GEN A1 - Schlipf, Jon A1 - Berkmann, Fritz A1 - Yamamoto, Yuji A1 - Reichenbach, Marc A1 - Veleski, Mitko A1 - Kawaguchi, Yuma A1 - Mörz, Florian A1 - Tomm, Jens W. A1 - Weißhaupt, David A1 - Fischer, Inga Anita T1 - Robust Si/Ge heterostructure metasurfaces as building blocks for wavelength-selective photodetectors T2 - Applied Physics Letters Y1 - 2023 U6 - https://doi.org/10.1063/5.0134458 SN - 1077-3118 VL - 122 IS - 12 ER - TY - GEN A1 - Han, Weijia A1 - Reiter, Sebastian A1 - Schlipf, Jon A1 - Mai, Christian A1 - Spirito, Davide A1 - Jose, Josmy A1 - Wenger, Christian A1 - Fischer, Inga Anita T1 - Strongly enhanced sensitivities of CMOS compatible plasmonic titanium nitride nanohole arrays for refractive index sensing under oblique incidence T2 - Optics Express N2 - Titanium nitride (TiN) is a complementary metal-oxide-semiconductor (CMOS) compatible material with large potential for the fabrication of plasmonic structures suited for device integration. However, the comparatively large optical losses can be detrimental for application. This work reports a CMOS compatible TiN nanohole array (NHA) on top of a multilayer stack for potential use in integrated refractive index sensing with high sensitivities at wavelengths between 800 and 1500 nm. The stack, consisting of the TiN NHA on a silicon dioxide (SiO2) layer with Si as substrate (TiN NHA/SiO2/Si), is prepared using an industrial CMOS compatible process. The TiN NHA/SiO2/Si shows Fano resonances in reflectance spectra under oblique excitation, which are well reproduced by simulation using both finite difference time domain (FDTD) and rigorous coupled-wave analysis (RCWA) methods. The sensitivities derived from spectroscopic characterizations increase with the increasing incident angle and match well with the simulated sensitivities. Our systematic simulation-based investigation of the sensitivity of the TiN NHA/SiO2/Si stack under varied conditions reveals that very large sensitivities up to 2305 nm per refractive index unit (nm RIU−1) are predicted when the refractive index of superstrate is similar to that of the SiO2 layer. We analyze in detail how the interplay between plasmonic and photonic resonances such as surface plasmon polaritons (SPPs), localized surface plasmon resonances (LSPRs), Rayleigh Anomalies (RAs), and photonic microcavity modes (Fabry-Pérot resonances) contributes to this result. This work not only reveals the tunability of TiN nanostructures for plasmonic applications but also paves the way to explore efficient devices for sensing in broad conditions. KW - TiN KW - Plasmonics Y1 - 2023 U6 - https://doi.org/10.1364/OE.481993 SN - 1094-4087 VL - 31 IS - 11 SP - 17389 EP - 17407 ER - TY - GEN A1 - Tetzner, Henriette A1 - Seifert, W. A1 - Skibitzki, Oliver A1 - Yamamoto, Yuji A1 - Lisker, Marco A1 - Mirza, M. M. A1 - Fischer, Inga Anita A1 - Paul, Douglas J. A1 - De Seta, Monica A1 - Capellini, Giovanni T1 - Unintentional p-type conductivity in intrinsic Ge-rich SiGe/Ge heterostructures grown on Si(001) T2 - Applied Physics Letter Y1 - 2023 U6 - https://doi.org/10.1063/5.0152962 SN - 1077-3118 VL - 122 IS - 24 ER - TY - GEN A1 - Hayat, Ahsan A1 - Spirito, Davide A1 - Corley-Wiciak, Agnieszka Anna A1 - Schubert, Markus Andreas A1 - Masood, Maria A1 - Reichmann, Felix A1 - Ratzke, Markus A1 - Capellini, Giovanni A1 - Fischer, Inga Anita T1 - MBE-based growth of Sn-rich quantum wells and dots at low Sn deposition rates T2 - Materials Science in Semiconductor Processing Y1 - 2023 U6 - https://doi.org/10.1016/j.mssp.2023.107693 SN - 1873-4081 VL - 165 ER - TY - GEN A1 - Steuer, O. A1 - Liedke, Maciej O. A1 - Butterling, M. A1 - Schwarz, D. A1 - Schulze, J. A1 - Li, Z. A1 - Wagner, A. A1 - Fischer, Inga Anita A1 - Hübner, R. A1 - Zhou, S. T1 - Evolution of point defects in pulsed-laser-melted Ge1-xSnx probed by positron annihilation lifetime spectroscopy T2 - Journal of Physics: Condensed Matter N2 - Direct-band-gap Germanium-Tin alloys (Ge1-xSnx) with high carrier mobilities are promising materials for nano- and optoelectronics. The concentration of open volume defects in the alloy, such as Sn and Ge vacancies, influences the final device performance. In this article, we present an evaluation of the point defects in molecular-beam-epitaxy grown Ge1-xSnx films treated by post-growth nanosecond-range pulsed laser melting (PLM). Doppler broadening – variable energy positron annihilation spectroscopy and variable energy positron annihilation lifetime spectroscopy are used to investigate the defect nanostructure in the Ge1-xSnx films exposed to increasing laser energy density. The experimental results, supported with ATomic SUPerposition calculations, evidence that after PLM, the average size of the open volume defects increases, which represents a raise in concentration of vacancy agglomerations, but the overall defect density is reduced as a function of the PLM fluence. At the same time, the positron annihilation spectroscopy analysis provides information about dislocations and Ge vacancies decorated by Sn atoms. Moreover, it is shown that the PLM reduces the strain in the layer, while dislocations are responsible for trapping of Sn and formation of small Sn-rich-clusters. KW - GeSn KW - laser annealing KW - positron annihilation KW - PLM KW - point defects Y1 - 2023 UR - https://iopscience.iop.org/article/10.1088/1361-648X/ad0a10/meta U6 - https://doi.org/10.1088/1361-648X/ad0a10 SN - 0953-8984 VL - 36 IS - 8 SP - 1 EP - 11 ER - TY - GEN A1 - Wen, Shuyu A1 - Shaikh, Mohd Saif A1 - Steuer, Oliver A1 - Prucnal, Slawomir A1 - Grenzer, Jörg A1 - Hübner, René A1 - Turek, Marcin A1 - Pyszniak, Krzysztof A1 - Reiter, Sebastian A1 - Fischer, Inga Anita A1 - Georgiev, Yordan M. A1 - Helm, Manfred A1 - Wu, Shaoteng A1 - Luo, Jun-Wei A1 - Zhou, Shengqiang A1 - Berencén, Yonder T1 - Room-temperature extended short-wave infrared GeSn photodetectors realized by ion beam techniques T2 - Applied Physics Letters N2 - GeSn alloys hold great promise as high-performance, low-cost, near- and short-wavelength infrared photodetectors with the potential to replace the relatively expensive and currently market-dominant InGaAs- and InSb-based photodetectors. In this Letter, we demonstrate room-temperature GeSn pn photodetectors fabricated by a complementary metal-oxide-semiconductor compatible process, involving Sn and P ion implantation and flash-lamp annealing prior to device fabrication. The fabrication process enables the alloying of Ge with Sn at concentrations up to 4.5% while maintaining the high-quality single-crystalline structure of the material. This allows us to create Ge0.955Sn0.045 pn photodetectors with a low dark current density of 12.8 mA/cm2 and a relatively high extended responsivity of 0.56 A/W at 1.71 μm. These results pave the way for the implementation of a cost-effective, scalable, and CMOS-compatible short-wavelength infrared detector technology. KW - Electric currents KW - Semiconductors KW - Photodetectors KW - C-MOS KW - Electromagnetic radiation detectors KW - Crystal structure KW - Alloys KW - Ion implantation KW - Ion beam analysis Y1 - 2023 UR - https://pubs.aip.org/aip/apl/article/123/8/081109/2907921 U6 - https://doi.org/10.1063/5.0166799 SN - 0003-6951 VL - 123 IS - 8 SP - 1 EP - 7 ER - TY - GEN A1 - Kalra, Amanpreet A1 - Alvarado Chavarin, Carlos A1 - Nitsch, Paul-Gregor A1 - Tschammer, Rudi A1 - Flege, Jan Ingo A1 - Ratzke, Markus A1 - Zoellner, Marvin Hartwig A1 - Schubert, Markus Andreas A1 - Wenger, Christian A1 - Fischer, Inga Anita T1 - Deposition of CeOₓ/SnOₓ-based thin films via RF magnetron sputtering for resistive gas sensing applications T2 - Physica B, Condensed matter N2 - Cerium oxide-tin oxide (CeOx/SnOx) thin films with varying Sn content were deposited using RF magnetron sputtering and investigated for hydrogen sensing applications. Structural, compositional, and morphological properties were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). Gas sensing measurements showed effective hydrogen detection at room temperature, with the sensitivity strongly influenced by Sn content and oxygen vacancy concentration. Higher Sn concentration enhanced the sensing response, which was correlated with microstructural features obtained from AFM and EDX, as well as with the presence of Ce3+ and Ce4+ oxidation states identified by XPS. This study highlights the potential of CeOx/SnOx thin films for possible back-end-of-line integration and provides proof-of-principle for room-temperature hydrogen sensing. KW - RF magnetron sputtering KW - CeOx/SnOx thin film KW - Room temperature KW - Hydrogen sensing Y1 - 2026 U6 - https://doi.org/10.1016/j.physb.2025.418098 SN - 0921-4526 VL - 723 SP - 1 EP - 7 PB - Elsevier BV CY - Amsterdam ER - TY - GEN A1 - Sengül, Akant A1 - Reiter, Sebastian A1 - Lotfi, Zahra A1 - Efremenko, Julia A1 - Laroussi, Arwa A1 - Corley-Wiciak, Agnieszka Anna A1 - Ratzke, Markus A1 - Mirsky, Vladimir M. A1 - Wenger, Christian A1 - Fischer, Inga Anita T1 - Titanium nitride plasmonic nanohole arrays with polymer coating : optical properties and their humidity-induced modifications T2 - Optical materials express N2 - The use of titanium nitride (TiN) for the fabrication of plasmonic structures such as nanohole arrays (NHAs) can enable their integration into optoelectronic devices on the silicon (Si) platform, for example, for the realization of on-chip chemical sensors and biosensors based on refractometric transduction. With a corresponding functionalization of the TiN nanohole arrays, these ultra-compact devices can be utilized in the development of various affinity sensors and sensor systems, such as cost-effective electronic noses for the early detection of gases in the food industry or agriculture. In this work, we focus on two types of coating for functionalization of TiN nanohole arrays: electrochemically synthesized poly-N-methylaniline and layer-by-layer deposited polyacrylic-acid/poly-allylamine (PAA/PAH). Our investigation comprises the experimental characterization of the optical properties of TiN nanhole arrays coated with polymer layers of different thicknesses as well as a comparison with simulation results. We demonstrate the potential of our setup sensing applications by measuring changes in optical properties of TiN nanohole arrays coated with PAA/PAH upon exposure to air of different humidity. Y1 - 2026 U6 - https://doi.org/10.1364/ome.578871 SN - 2159-3930 VL - 16 IS - 2 SP - 184 EP - 196 PB - Optica Publishing Group CY - Washington, DC ER -