@misc{WeisshauptSuergersBloosetal.,
author = {Weißhaupt, David and S{\"u}rgers, Christoph and Bloos, Dominik and Funk, Hannes Simon and Oehme, Michael and Fischer, Gerda and Schubert, Markus Andreas and Wenger, Christian and van Slageren, Joris and Fischer, Inga Anita and Schulze, J{\"o}rg},
title = {Lateral Mn5Ge3 spin-valve in contact with a high-mobility Ge two-dimensional hole gas},
series = {Semiconductor Science and Technology},
volume = {39},
journal = {Semiconductor Science and Technology},
number = {12},
publisher = {IOP Publishing},
issn = {0268-1242},
doi = {10.1088/1361-6641/ad8d06},
pages = {1 -- 10},
abstract = {Abstract Ge two-dimensional hole gases (2DHG) in strained modulation-doped quantum-wells represent a promising material platform for future spintronic applications due to their excellent spin transport properties and the theoretical possibility of efficient spin manipulation. Due to the continuous development of epitaxial growth recipes extreme high hole mobilities and low effective masses can be achieved, promising an efficient spin transport. Furthermore, the Ge 2DHG can be integrated in the well-established industrial complementary metal-oxide-semiconductor (CMOS) devices technology. However, efficient electrical spin injection into a Ge 2DHG—an essential prerequisite for the realization of spintronic devices—has not yet been demonstrated. In this work, we report the fabrication and low-temperature magnetoresistance (MR) measurements of a laterally structured Mn5Ge3/Ge 2DHG/ Mn5Ge3 device. The ferromagnetic Mn5Ge3 contacts are grown directly into the Ge quantum well by means of an interdiffusion process with a spacing of approximately 130 nm, forming a direct electrical contact between the ferromagnetic metal and the Ge 2DHG. Here, we report for the first time a clear MR signal for temperatures below 13 K possibly arising from successful spin injection into the high mobility Ge 2DHG. The results represent a step forward toward the realization of CMOS compatible spintronic devices based on a 2DHG.},
language = {en}
}
@misc{EfremenkoLaroussiSengueletal.,
author = {Efremenko, Yulia and Laroussi, Arwa and Seng{\"u}l, Akant and Corley-Wiciak, Agnieszka Anna and Fischer, Inga Anita and Mirsky, Vladimir M.},
title = {Deposition of Polymers on Titanium Nitride Electrodes},
series = {Coatings},
volume = {14},
journal = {Coatings},
number = {2},
issn = {2079-6412},
doi = {10.3390/coatings14020215},
abstract = {The application of titanium nitride (TiN) as an electrode for electrochemical deposition or characterization requires the removal of an insulating layer from its surface. This process was studied and optimized, and the conditions for the complete removal of this layer through treatment with oxalic acid were formulated. The obtained TiN surfaces were used for the deposition of various conducting and non-conducting polymers. Two different approaches were applied: (i) in situ electrochemical synthesis of the main classes of conducting polymers, including polyaniline, polypyrrole, polythiophene, and selected derivatives thereof, and (ii) electrostatically driven layer-by-layer (LbL) deposition of multilayers of oppositely charged polyelectrolytes. The deposited polymers were characterized by electrochemical methods. The electrochemical properties of the deposited conducting polymers and their deposition on the TiN surface were comparable to those of the metallic electrodes. The films produced via LbL deposition exhibited a pronounced influence of the charge of the last deposited polymer on the redox reaction of ferri/ferrocyanide, validating the charge alteration with each successive polymer layer deposition. The studied deposition technologies can be used for the modification of TiN surfaces required in applications of this material in chemical sensors and other devices.},
language = {en}
}
@misc{OleynikBerkmannReiteretal.,
author = {Oleynik, Paul and Berkmann, Fritz and Reiter, Sebastian and Schlipf, Jon and Ratzke, Markus and Yamamoto, Yuji and Fischer, Inga Anita},
title = {Strong Optical Coupling of Lattice Resonances in a Top-down Fabricated Hybrid Metal-Dielectric Al/Si/Ge Metasurface},
series = {Nano Letters},
volume = {24},
journal = {Nano Letters},
number = {10},
issn = {1530-6984},
doi = {10.1021/acs.nanolett.3c05050},
pages = {3142 -- 3149},
abstract = {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.},
language = {en}
}
@misc{KostoTschammerMoralesetal.,
author = {Kosto, Yuliia and Tschammer, Rudi and Morales, Carlos and Henkel, Karsten and Flege, Jan Ingo and Ratzke, Markus and Fischer, Inga Anita and Costina, Ioan and Alvarado Chavarin, Carlos and Wenger, Christian},
title = {Rational design and development of room temperature hydrogen sensors compatible with CMOS technology: a necessary step for the coming renewable hydrogen economy},
series = {Proceedings of iCampus Conference Cottbus 2024},
journal = {Proceedings of iCampus Conference Cottbus 2024},
publisher = {AMA Service GmbH},
address = {Wunstorf},
isbn = {978-3-910600-00-3},
doi = {10.5162/iCCC2024/P21},
pages = {182 -- 185},
abstract = {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.},
language = {en}
}
@misc{BeckerStorckLiuetal.,
author = {Becker, L. and Storck, Peter and Liu, Y. and Schwalb, G. and Schroeder, Thomas and Fischer, Inga Anita and Albrecht, M.},
title = {Optimizing misfit dislocation glide kinetics for enhanced threading dislocation density reduction in Si1- xGex/Si (001) layers through dynamic growth rate control},
series = {Journal of Applied Physics},
volume = {135},
journal = {Journal of Applied Physics},
number = {20},
issn = {0021-8979},
doi = {10.1063/5.0204318},
pages = {10},
language = {en}
}
@misc{BerkmannPovolniSchwarzetal.,
author = {Berkmann, Fritz and Povolni, Pavel and Schwarz, Daniel and Fischer, Inga Anita},
title = {Influence of material and geometry parameters on resonance linewidths of plasmonic modes in gratings made from highly doped Ge1-xSnx},
series = {Journal of Physics D: Applied Physics},
volume = {57},
journal = {Journal of Physics D: Applied Physics},
number = {43},
doi = {10.1088/1361-6463/ad67ea},
pages = {10},
language = {en}
}
@misc{HayatRatzkeAlvaradoChavarinetal.,
author = {Hayat, Ahsan and Ratzke, Markus and Alvarado Chavarin, Carlos and Z{\"o}llner, Marvin Hartwig and Corley-Wiciak, Agnieszka Anna and Schubert, Markus Andreas and Wenger, Christian and Fischer, Inga Anita},
title = {Structural and morphological properties of CeO2 films deposited by radio frequency magnetron sputtering for back-end-of-line integration},
series = {Thin Solid Films},
volume = {807},
journal = {Thin Solid Films},
issn = {0040-6090},
doi = {10.1016/j.tsf.2024.140547},
pages = {3},
language = {en}
}
@misc{ReiterSenguelMaietal.,
author = {Reiter, Sebastian and Seng{\"u}l, Akant and Mai, Christian and Spirito, Davide and Wenger, Christian and Fischer, Inga Anita},
title = {On-chip refractive index sensors based on plasmonic TiN Nanohole Arrays},
series = {2024 IEEE Silicon Photonics Conference (SiPhotonics)},
journal = {2024 IEEE Silicon Photonics Conference (SiPhotonics)},
isbn = {979-8-3503-9404-7},
issn = {1949-209X},
doi = {10.1109/SiPhotonics60897.2024.10544048},
pages = {2},
language = {de}
}
@misc{JoseMaiWengeretal.,
author = {Jose, Josmy and Mai, Christian and Wenger, Christian and Fischer, Inga Anita},
title = {Integration concept of plasmonic TiN nanohole arrays in a 200 mm BiCMOS Si technology for refractive index sensor applications},
series = {iCCC2024 - iCampµs Cottbus Conference},
journal = {iCCC2024 - iCampµs Cottbus Conference},
doi = {10.5162/iCCC2024/7.2},
pages = {96 -- 99},
language = {de}
}
@misc{MaiPeczekKrohetal.,
author = {Mai, Christian and Peczek, Anna and Kroh, Aleksandra and Jose, Josmy and Reiter, Sebastian and Wenger, Christian and Fischer, Inga Anita},
title = {Towards a CMOS compatible refractive index sensor: cointegration of TiN nanohole arrays and Ge photodetectors in a 200 mm wafer silicon technology},
series = {Optics Express},
volume = {32},
journal = {Optics Express},
number = {17},
publisher = {Optica Publishing Group},
issn = {1094-4087},
doi = {10.1364/OE.530081},
pages = {29099 -- 29111},
abstract = {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\%.},
language = {en}
}
@misc{BerkmannSteuerGanssetal.,
author = {Berkmann, Fritz and Steuer, Oliver and Ganss, Fabian and Prucnal, Slawomir and Schwarz, Daniel and Fischer, Inga Anita and Schulze, J{\"o}rg},
title = {Sharp MIR plasmonic modes in gratings made of heavily doped pulsed laser-melted Ge1-xSnx},
series = {Optical Materials Express},
volume = {13},
journal = {Optical Materials Express},
number = {3},
issn = {2159-3930},
doi = {10.1364/OME.479637},
pages = {752 -- 763},
language = {en}
}
@misc{WeisshauptFunkOehmeetal.,
author = {Weißhaupt, David and Funk, Hannes S. and Oehme, Michael and Bloos, Dominik and Berkmann, Fritz and Seidel, Lukas and Fischer, Inga Anita and Schulze, J{\"o}rg},
title = {High mobility Ge 2DHG based MODFETs for low-temperature applications},
series = {Semiconductor Science and Technology},
volume = {38},
journal = {Semiconductor Science and Technology},
number = {3},
issn = {1361-6641},
doi = {10.1088/1361-6641/acb22f},
language = {en}
}
@misc{ReiterHanMaietal.,
author = {Reiter, Sebastian and Han, Weijia and Mai, Christian and Spirito, Davide and Jose, Josmy and Z{\"o}llner, Marvin Hartwig and Fursenko, Oksana and Schubert, Markus Andreas and Stemmler, Ivo and Wenger, Christian and Fischer, Inga Anita},
title = {Titanium Nitride Plasmonic Nanohole Arrays for CMOS-compatible integrated refractive index sensing: influence of layer thickness on optical properties},
series = {Plasmonics},
journal = {Plasmonics},
issn = {1557-1963},
doi = {10.1007/s11468-023-01810-3},
pages = {1 -- 13},
language = {en}
}
@misc{HanReiterSchlipfetal.,
author = {Han, Weijia and Reiter, Sebastian and Schlipf, Jon and Mai, Christian and Spirito, Davide and Jose, Josmy and Wenger, Christian and Fischer, Inga Anita},
title = {Strongly enhanced sensitivities of CMOS compatible plasmonic titanium nitride nanohole arrays for refractive index sensing under oblique incidence},
series = {Optics Express},
volume = {31},
journal = {Optics Express},
number = {11},
issn = {1094-4087},
doi = {10.1364/OE.481993},
pages = {17389 -- 17407},
abstract = {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-P{\´e}rot 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.},
language = {en}
}
@misc{SteuerLiedkeButterlingetal.,
author = {Steuer, O. and Liedke, Maciej O. and Butterling, M. and Schwarz, D. and Schulze, J. and Li, Z. and Wagner, A. and Fischer, Inga Anita and H{\"u}bner, R. and Zhou, S.},
title = {Evolution of point defects in pulsed-laser-melted Ge1-xSnx probed by positron annihilation lifetime spectroscopy},
series = {Journal of Physics: Condensed Matter},
volume = {36},
journal = {Journal of Physics: Condensed Matter},
number = {8},
issn = {0953-8984},
doi = {10.1088/1361-648X/ad0a10},
pages = {1 -- 11},
abstract = {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.},
language = {en}
}
@misc{WenShaikhSteueretal.,
author = {Wen, Shuyu and Shaikh, Mohd Saif and Steuer, Oliver and Prucnal, Slawomir and Grenzer, J{\"o}rg and H{\"u}bner, Ren{\´e} and Turek, Marcin and Pyszniak, Krzysztof and Reiter, Sebastian and Fischer, Inga Anita and Georgiev, Yordan M. and Helm, Manfred and Wu, Shaoteng and Luo, Jun-Wei and Zhou, Shengqiang and Berenc{\´e}n, Yonder},
title = {Room-temperature extended short-wave infrared GeSn photodetectors realized by ion beam techniques},
series = {Applied Physics Letters},
volume = {123},
journal = {Applied Physics Letters},
number = {8},
issn = {0003-6951},
doi = {10.1063/5.0166799},
pages = {1 -- 7},
abstract = {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.},
language = {en}
}
@misc{SchlipfCutoloManganellietal.,
author = {Schlipf, Jon and Cutolo, Maria Alessandra and Manganelli, Costanza Lucia and Reiter, Sebastian and Seibold, G{\"o}tz and Skibitzki, Oliver and Wenger, Christian and Fischer, Inga Anita},
title = {Fabrication and optical characterization of CMOS-compatible honeycomb-like large-scale lattices of near-field coupled plasmonic TiN nanotriangles},
series = {Advanced optical materials},
volume = {2025},
journal = {Advanced optical materials},
publisher = {Wiley-VCH},
address = {Weinheim},
issn = {2195-1071},
doi = {10.1002/adom.202403408},
pages = {1 -- 8},
abstract = {Honeycomb-like plasmonic titanium nitride nanotriangle arrays defined by photolithography and fabricated in a modified silicon-germanium electronic-photonic integrated circuit process in a state-of-the-art pilot line. The nanotriangle arrays are characterized in experiments and simulations. The momentum-dependent reflectance spectra exhibit not only features that are consistent with surface lattice resonances in the honeycomb lattice but also minima governed by near-field coupling of the individual nanotriangles. The optical characterization results in combination with simulation-based predictions indicate that such nanotriangle arrays are capable of supporting collective plasmonic resonances that can be described as massless Dirac particles. The fabrication approach opens up the possibility of integrating the structures into device fabrication processes, and avenues toward near-infrared sensing and communication applications are predicted.},
language = {en}
}