Article
Chemistry, Multidisciplinary
Ming Ming, Fei Gao, Jian-Huan Wang, Jie-Yin Zhang, Ting Wang, Yuan Yao, Hao Hu, Jian-Jun Zhang
Summary: Ordered Ge hut wires are synthesized on patterned Si (001) substrates through multilayer heteroepitaxy, achieving self-assembled growth inside patterned trenches with a smooth surface. These embedded GeSi wires induce tensile strain on the Si surface, leading to preferential nucleation of Ge nanostructures. By tuning the growth conditions, ordered Ge nano-dashes, disconnected wires, and continuous wires are obtained. The site-controlled Ge nanowires on a flattened surface enable easy fabrication and large-scale integration of nanowire quantum devices.
Article
Energy & Fuels
Ivan Garcia, Laura Barrutia, Shabnam Dadgostar, Manuel Hinojosa, Andrew Johnson, Ignacio Rey-Stolle
Summary: Efforts to reduce the formation of cracks during growth of GaInP/GaInAs/Ge 3-junction solar cells on Ge|Si virtual substrates have been made by thinning the structure. Theoretical analysis suggests that the GaInAs middle cell can be drastically thinned while maintaining efficiency. Experimental results demonstrate that the formation of cracks is prevented in thinned structures.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2021)
Article
Multidisciplinary Sciences
A. A. Shklyaev, D. E. Utkin, A. V. Tsarev, S. A. Kuznetsov, K. V. Anikin, A. V. Latyshev
Summary: The light reflection properties of Ge disk lattices on Si substrates were studied, revealing the impact of gap widths on the reflection performance. A deeper reflection minimum can be achieved with smaller gap widths. These observations are associated with the resonant fields around the closely spaced disks according to numerical simulation data.
SCIENTIFIC REPORTS
(2022)
Article
Chemistry, Multidisciplinary
Roberto Bergamaschini, Rianne C. Plantenga, Marco Albani, Emilio Scalise, Yizhen Ren, Hakon Ikaros T. Hauge, Sebastian Kolling, Francesco Montalenti, Erik P. A. M. Bakkers, Marcel A. Verheijen, Leo Miglio
Summary: Formation of Ge-rich prismatic inclusions in the hexagonal SiGe shell of GaP-Si-SiGe nanowires is reported and discussed. A phase-field growth model reveals a kinetic segregation process due to different surface mobilities of Ge and Si, leading to the formation of prisms. The control of GaP core faceting and modulation of shell growth rate allow for direct control of the size and appearance of the Ge-rich prisms, paving the way for advanced band-gap-engineering designs.
Article
Chemistry, Physical
Malgorzata Sojka, Justyna Zeler, Eugeniusz Zych
Summary: Oxyorthosilicates have a long history in luminescent applications, such as phosphors and scintillators. This study provides detailed research on the thermoluminescent properties of Y-2(Ge-x,Si1-x)O-5:Pr, exploring the management of electron trap depths by adjusting the Ge/Si ratio. Strong thermoluminescence is observed from all compositions after X-ray radiation, but the efficiency of charging traps with UV-C photons decreases systematically as the Si content increases.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Energy & Fuels
Hosni Meddeb, Maximilian Goetz-Koehler, Christoph Flathmann, Michael Seibt, Kai Gehrke, Martin Vehse
Summary: This paper reports the first demonstration of a novel semi-transparent solar cell based on ultrathin hydrogenated amorphous Si/Ge multiple quantum wells (MQW). The advantages of ultrathin MQW as photoactive material to overcome the limitations of thin and ultrathin single quantum well (SQW) counterparts are explained. The use of MQW leads to an improvement in power conversion efficiency and light utilization efficiency.
PROGRESS IN PHOTOVOLTAICS
(2022)
Article
Engineering, Electrical & Electronic
M. Salem, J. Salem, H. Ghannam, I. Massoudi, F. Bourguiba, M. Gaidi
Summary: Undoped and Fe doped ZnO thin films were prepared by a simple and low-cost co-precipitation method and deposited on silicon substrates using the spin-coating technique. The influence of Fe-doping concentration on the structural and opto-electronic properties of the films was investigated. XRD and AFM techniques were used to analyze the crystalline structure and surface morphology of the deposited films, while FTIR and photoconductance-based methods were employed to study the surface passivation and reflectivity. The results showed that the effective minority carrier lifetime increased from 2 to 95 μs with a minority carrier density of 10^13 cm^(-3), and the reflectance decreased from 32% to approximately 6% after Fe-doped ZnO coating on silicon.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2023)
Article
Chemistry, Inorganic & Nuclear
Zhen Gao, Yao He, Kai Xiong
Summary: In this work, novel two-dimensional Janus monolayers, SZrAZ(2), were introduced and their controllable electronic properties under strain and an external electric field were investigated. The results showed that these monolayers exhibited properties of indirect band gap semiconductors in equilibrium state. However, under biaxial strain and an external electric field, some of the monolayers transitioned from semiconducting to metallic behavior. The research findings lay the foundation for utilizing two-dimensional Janus materials in electronic devices.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Multidisciplinary
Seamus Kilian, Kieran McCarthy, Killian Stokes, Temilade Esther Adegoke, Michele Conroy, Ibrahim Saana Amiinu, Hugh Geaney, Tadhg Kennedy, Kevin M. Ryan
Summary: The study describes a method of electroplating metallic Zn seeds on stainless steel substrates to grow Si and Ge nanowires. The use of Zn as a catalyst produces defect-rich Si NWs with high discharge capacity and stable cycling performance. The Zn seeds actively participate in Li-cycling activities, resulting in a highly porous network structure for improved performance.
Article
Biochemistry & Molecular Biology
Ewa Dumiszewska, Pawel Ciepielewski, Piotr A. Caban, Iwona Jozwik, Jaroslaw Gaca, Jacek M. Baranowski
Summary: This study investigates the problem of graphene protection of Ge surfaces against oxidation. The results show that water vapor can penetrate through graphene defects on Ge(001)/Si(001) substrates, leading to the formation of GeO2. The presence of GeO2 blisters under graphene significantly enhances the Raman spectrum of graphene.
Article
Materials Science, Multidisciplinary
Renjiu Hu, Zhiting Tian
Summary: This work presents direct evidence of phonon Anderson localization by observing the exponential decay of mode-resolved transmissions. The study successfully captures localized modes in different structures, even when thermal conductivity trend is monotonically upward.
Article
Chemistry, Multidisciplinary
Max Franck, Jaroslaw Dabrowski, Markus Andreas Schubert, Christian Wenger, Mindaugas Lukosius
Summary: In this study, the growth of hexagonal boron nitride (hBN) on epitaxial Ge(001)/Si substrates using high-vacuum chemical vapor deposition from borazine was systematically investigated for the first time. The research findings suggest that the process pressure and growth temperature have certain influences on the morphology, growth rate, and crystalline quality of hBN films.
Article
Multidisciplinary Sciences
Marco Albani, Roberto Bergamaschini, Andrea Barzaghi, Marco Salvalaglio, Joao Valente, Douglas J. Paul, Axel Voigt, Giovanni Isella, Francesco Montalenti
Summary: The development of three-dimensional architectures in semiconductor technology is enabling new device concepts and applications, with predictive simulation tools playing a key role in guiding experiments. A versatile phase-field model is applied to the growth of three-dimensional microcrystals, offering a guideline for designing new 3D heterostructures.
SCIENTIFIC REPORTS
(2021)
Article
Energy & Fuels
Monalisa Ghosh, Pavel Bulkin, Francois Silva, Erik Johnson, Ileana Florea, Daniel Funes-Hernando, Alexandre Tanguy, Charles Renard, Nicolas Vaissiere, Jean Decobert, Ivan Garcia, Ignacio Rey-Stolle, Pere Roca Cabarrocas
Summary: This study demonstrates a low-cost approach to tandem solar cells by depositing ultrathin epitaxial films of germanium on silicon wafers as virtual substrates for the growth of III-V materials. The optimized plasma-enhanced chemical vapor deposition process allows for direct growth of germanium films on silicon wafers, which can withstand high-temperature annealing. III-V layers deposited on the virtual substrates exhibit comparable properties to those deposited on silicon wafers.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2022)
Article
Crystallography
S. A. Rudin, V. A. Zinovyev, Zh. V. Smagina, P. L. Novikov, A. V. Nenashev, K. V. Pavsky
Summary: This study investigates the growth of ordered arrays of Ge quantum dot groups on deep-pit-patterned SOI substrates, finding that the quantum dots are located at the periphery of the pits. It is demonstrated that the number of quantum dots per pit can be controlled by varying the period of the pit lattice. Monte Carlo simulations suggest that the island patterning is a result of competition between stress-driven quantum dot nucleation and Ge migration downward into the pits.
JOURNAL OF CRYSTAL GROWTH
(2022)
Article
Engineering, Electrical & Electronic
B. Das, J. Schulze, U. Ganguly
Summary: The article proposes an epitaxial vertical biristor with an asymmetric doping profile to achieve sub-bandgap impact ionization in the negative polarity. Experimental results demonstrate low latch-up voltage, faster programming, and a larger read window for the device.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Editorial Material
Engineering, Electrical & Electronic
Paul R. Berger, Muhammad Mustafa Hussain, Francesca Iacopi, Jorg Schulze, Peide Ye, Willy Rachmady, Huang-Chun Wen, Siddharth Krishnan
Summary: Thermal budgets are hindering leading-edge ultra-scaled and novel designs, and the transition to reduced temperature processing is becoming a significant impediment globally.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Physics, Applied
Fritz Berkmann, Markus Ayasse, Jon Schlipf, Florian Moerz, David Weisshaupt, Michael Oehme, Slawomir Prucnal, Yuma Kawaguchi, Daniel Schwarz, Inga Anita Fischer, Joerg Schulze
Summary: This study investigates the potential of highly n-doped Ge1-y Sn (y) films grown directly on Si as plasmonic grating structures, showing that increasing Sn content may improve performance for plasmonic applications, but the material quality needs to be improved to fully utilize the benefits.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Robin Khosla, Daniel Schwarz, Hannes S. Funk, Kateryna Guguieva, Joerg Schulze
Summary: In this study, comprehensive investigations were conducted on aluminum oxide high-k gate oxides deposited via remote plasma enhanced atomic layer deposition (Re-PEALD) in a commercial reactor, revealing the optimal growth conditions and characteristics of high-quality aluminum oxide thin films for various nanoelectronics applications.
SOLID-STATE ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Sumit Choudhary, Daniel Schwarz, Hannes S. Funk, D. Weisshaupt, Robin Khosla, Satinder K. Sharma, Joerg Schulze
Summary: The integration of ferroelectric hafnium zirconium oxide (HZO) over the p-Ge/n-Ge(-on-)n-Si system is achieved for the first time in this study. A carrier modulation approach using depletion approximation and negative capacitance is employed to fabricate HZO and thin p-Ge channel-based FET. The optimized TaN/HZO/TaN stacks exhibit enhanced ferroelectricity and non-centrosymmetric orthorhombic phase.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Physics, Applied
Yufang Xie, Magdalena Birowska, Hannes Simon Funk, Inga Anita Fischer, Daniel Schwarz, Joerg Schulze, Yu-Jia Zeng, Manfred Helm, Shengqiang Zhou, Slawomir Prucnal
Summary: We report a change in the structural and magnetic properties of epitaxial Mn5Ge3 on a Ge-on-Si (111) substrate by applying strain engineering through ms-range flash lamp annealing (FLA). X-ray diffraction results demonstrate that during FLA for 20 ms, the formation of nonmagnetic MnxGey secondary phases is suppressed, while the in-plane expansion of the lattice increases with increasing annealing temperature. Temperature-dependent magnetization results indicate that the Curie temperature of Mn5Ge3 rises from 287 K in the as-prepared sample to above 400 K after FLA, making Mn5Ge3 an attractive material for spintronics. Experimental results together with theoretical Monte Carlo simulations allow us to conclude that the expansion of the in-plane lattice causes the increase of the Curie temperature due to enhancement of the ferromagnetic interaction between Mn atoms.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Hannes S. Funk, Michal Kern, David Weisshaupt, Christoph Suergers, Inga A. Fischer, Michael Oehme, Joris van Slageren, Joerg Schulze
Summary: This study investigates the structure and magnetic properties of Mn-based ferromagnetic layers on the semiconductor SixGe1-x-ySny with different Sn content compared to layers on Ge and Si0.75Ge0.25. The samples exhibit phase separation into Si-rich and Ge-rich Mn compounds, with all samples being ferromagnetic. Saturation magnetization decreases and coercive field increases with higher Si content x. The Curie temperature does not show a clear trend with increasing Si content. Based on composition, structure, and magnetic properties, a two-layer model is proposed to explain the observed magnetic behavior with Si content playing a key role.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Engineering, Electrical & Electronic
Yasmine Elogail, Fritz Berkmann, Caterina J. Clausen, Inga A. Fischer, Linda A. Haenel, Daniel Schwarz, Joerg Schulze
Summary: Ge-based p-channel FETs are considered promising devices to replace Si-based p-channel FETs and reduce power consumption. PDBFETs are good candidates for tuning the performance of Ge-based FETs by using almost undoped channels to create necessary barriers. This study aims to demonstrate the capability of the PDBFET concept to improve Ge-based device performance, even on large scaled devices.
MICROELECTRONICS JOURNAL
(2022)
Article
Engineering, Electrical & Electronic
Michael Oehme, Erich Kasper, David Weisshaupt, Eric Sigle, Tim Hersperger, Maurice Wanitzek, Daniel Schwarz
Summary: Two-dimensional hole gases are demonstrated in modulation doped Si (x) Ge1-x-y Sn (y) quantum wells embedded in Si0.2Ge0.8 barrier layers. The fabrication of modulation doped QW structures is achieved using molecular beam epitaxy on a virtual SiGe substrate. The lattice spacing of the SiGe-VS can be varied by controlling the annealing temperature. The electrical conductivity, sheet hole density, and mobility of the channels show temperature dependence. Alloy scattering dominates the low-temperature mobility by introducing Sn or Si into the Ge reference well. At low temperatures, there is a linear relationship between the charge transfer and the lattice mismatch in modulated doped QW structures.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Fritz Berkmann, Lion Augel, Michael Hack, Yuma Kawaguchi, David Weisshaupt, Inga A. Fischer, Joerg Schulze
Summary: By optimizing the layer structure and geometry, plasmonic nanohole arrays can be used to sense refractive index changes in vertical Ge-on-Si PIN photodiodes, enabling fully integrated biosensors with high sensitivities and small footprint.
IEEE PHOTONICS JOURNAL
(2022)
Proceedings Paper
Computer Science, Hardware & Architecture
Lukas Seidel, Soeren Schaefer, Michael Oehme, Dan Buca, Giovanni Capellini, Joerg Schulze, Daniel Schwarz
Summary: This study presents the growth, fabrication, and characterization of Ge1-ySny and SixGe1-x-ySny/Ge1-ySny pin-diodes by molecular beam epitaxy. The crystal analysis shows that the Ge1-ySny pin-diode is lattice-matched grown, while the SixGe1-x-ySny/Ge1-ySny pin-diode is pseudomorphic with respect to the buffer. The direct current measurements reveal a shift in threshold voltage and metallic behavior in series resistance. Moreover, the electroluminescence spectra show a significantly higher signal in cryogenic temperatures for both Ge1-ySny and SixGe1-x-ySny/Ge1-ySny pin-diodes. The peak energies at an injection current density of 2.5 kA/cm(2) are 575 meV and 610 meV, respectively.
ESSCIRC 2022- IEEE 48TH EUROPEAN SOLID STATE CIRCUITS CONFERENCE (ESSCIRC)
(2022)
Proceedings Paper
Computer Science, Hardware & Architecture
Maurice Wanitzek, Michael Oehme, Christian Spieth, Daniel Schwarz, Lukas Seidel, Jorg Schulze
Summary: In this work, GeSn-on-Si Avalanche Photodiodes with a Sn concentration of up to 2.2% were grown, fabricated, and characterized. The Ge1-xSnx absorption layer was grown at a low temperature of 200 degrees C using molecular beam epitaxy. The results showed significantly increased absorption for a wavelength of 1,550 nm, while the dark currents were limited by a perimeter leakage path and not influenced by the Sn concentration.
ESSCIRC 2022- IEEE 48TH EUROPEAN SOLID STATE CIRCUITS CONFERENCE (ESSCIRC)
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
T. Bernhard, R. Massey, Zhiou Li, Joerg-F Schulze, K. Klaeden, S. Zarwell, E. Steinhaeuser, F. Bruening
Summary: Flexible printed circuit boards are increasingly important in the electronics industry. A roll-anneal process is used to create a highly flexible copper foil with large crystallites, preventing stress accumulation and metal fatigue. The production of FPCBs involves laminating roll-annealed foils onto flexible polymers and using sophisticated plating processes for different foil materials. The choice of stabilizer system in the plating process affects the bottom-up recrystallization of the galvanic Cu layer.
IEEE 72ND ELECTRONIC COMPONENTS AND TECHNOLOGY CONFERENCE (ECTC 2022)
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
B. Marzban, L. Seidel, V Kiyek, T. Liu, M. Zoellner, Z. Ikonic, G. Capellini, D. Buca, J. Schulze, M. Oehme, J. Witzens
Summary: We propose a suspended SiGeSn microring laser design that utilizes strain and composition to engineer the band structure, resulting in a higher energy difference and direct bandgap. Experimental results confirm the effectiveness of our approach.
SILICON PHOTONICS XVII
(2022)
Article
Engineering, Electrical & Electronic
Sumit Choudhary, Daniel Schwarz, Hannes S. Funk, Robin Khosla, Satinder K. Sharma, Joerg Schulze
Summary: This study investigated the deposition of HfO2 dielectric on p-Ge(-on-)p-Si stack using nanoscopic and microscopic probes, revealing the phenomenon of trapped charges and analyzing its disintegration. The impact of constant voltage stress on trapped charges was studied, as well as its effects on threshold voltage and hysteresis window. Additionally, the variations in cyclic C-V characteristics and gate leakage current density under different stress levels were examined.
IEEE TRANSACTIONS ON NANOTECHNOLOGY
(2021)
