Article
Chemistry, Physical
Yongjoon Choi, Choonghee Cho, Dongmin Yoon, Joosung Kang, Jihye Kim, So Young Kim, Dong Chan Suh, Dae-Hong Ko
Summary: We investigated the selective etching of Si versus Si1-xGex with different Ge concentrations. The etching rate of Si1-xGex decreases with increasing Ge concentration due to the reduction in Si(Ge)-OH bond. The morphology of the etched surfaces and the etching rate depend on the surface orientation and the presence of Triton X-100 in TMAH solution.
Article
Chemistry, Physical
Elie Assaf, Isabelle Berbezier, Mohammed Bouabdellaoui, Marco Abbarchi, Antoine Ronda, Damien Valenducq, Fabien Deprat, Olivier Gourhant, Andreas Campos, Luc Favre
Summary: We have developed a new high temperature, ultra-low rate oxidation process that can produce defect-free, fully strained, and perfectly flat Silicon Germanium (Si1-xGex) On Insulator films. By using this process, we discovered a new mechanism of elastic strain relaxation for larger Ge concentrations. The relaxation occurs through the undulation of the Si1-xGex layer without nucleation of dislocations. This study demonstrates the potential for using SiO2 as a compliant substrate for strain engineering and the possibility of applying this relaxation process to other systems beyond Si1-xGex films.
APPLIED SURFACE SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Junichi Murota, Hiromu Ishii
Summary: The in-situ doping process of B and P in CVD Si and Si1-xGex (100) epitaxial growth was investigated using SiH4-GeH4-dopant gas (B2H6 or PH3)-H2 gas mixture. The study proposed mechanisms for in situ doping at different dopant gas partial pressures and showed good agreement with experimental data.
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Amita Rawat, Krista Khiangte Roluahpuia, Philipp Gribisch, H-J Osten, Apurba Laha, Suddhasatta Mahapatra, Udayan Ganguly
Summary: Germanium-on-insulator (GeOI) technology is a potential alternative to bulk-silicon based devices for radiofrequency (RF) and complementary metal oxide semiconductor applications. Despite the high cost of GeOI wafers, it enables the growth of high mobility transistors.
Article
Crystallography
A. V. Klekovkin, V. P. Martovitsky, V. A. Tsvetkov, E. A. Pershina
Summary: In Si(0 0 1)\(Si1-xGex 6-8 nm + Si 100-120 nm) x 2 (0.07 < x < 0.21) structures grown by MBE, X-ray reflectometry and diffraction were used to study the thickness variation. It was found that the second period thickness was smaller compared to the first period due to increasing misfit energy. Electron microscopy confirmed the smaller thickness of the second period. Three-waves diffraction on the forbidden reflection (002) showed different structural perfection values in two azimuthal directions. In the same sample, the reflectometry-determined average period was larger than the diffraction-determined period, and the angular distance between satellites on curves (002) corresponded to two different period values.
JOURNAL OF CRYSTAL GROWTH
(2023)
Article
Engineering, Electrical & Electronic
Hsien-Wen Wan, Yi-Ting Cheng, Chao-Kai Cheng, Yu-Jie Hong, Tien-Yu Chu, Mu-Tung Chang, Chia-Hung Hsu, Jueinai Kwo, Minghwei Hong
Summary: In this study, the deposition of epitaxial Si on Si1-xGex at high temperatures and subsequent deposition of HfO2 on the epi-Si surface have effectively improved the trap density and reliability of pMOS devices with high Ge contents, indicating their potential for sub-3 nm complementary MOS technology.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
Article
Chemistry, Physical
Jesse A. Johnson II, Ryan Need, David Brown, Chris Hatem, Bruce Adams, Xuebin Li, Kevin S. Jones
Summary: This study investigated the relaxation mechanism of Si1-xGex/Si heterostructures under pulsed laser melting and identified surface dislocation half-loops as the primary strain relieving defects. The findings have implications for understanding the potential applications of pulsed laser melting in pMOS source/drain contact engineering.
SURFACES AND INTERFACES
(2022)
Article
Physics, Applied
Alisha Nanwani, Ravindra Singh Pokharia, Jan Schmidt, H. J. Osten, Suddhasatta Mahapatra
Summary: The role of post-growth cyclic annealing (PGCA) and subsequent regrowth in improving the crystal quality and surface morphology of (111)-oriented Ge epitaxial layers grown by low temperature molecular beam epitaxy is investigated. It is found that PGCA effectively suppresses planar defects in Ge(111) epilayers. Additionally, PGCA promotes adatom down-climb and heals the surface morphology, leading to further improvement upon Ge regrowth.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Rekha R. Schnepf, M. Brooks Tellekamp, Theresa Saenz, John S. Mangum, Edwin Supple, Dennice M. Roberts, Craig L. Perkins, Karen N. Heinselman, Brian P. Gorman, Ann L. Greenaway, Eric S. Toberer, Adele C. Tamboli
Summary: This paper reports on the growth of epitaxial ZnGeP2 on Si and GaP substrates via reactive combinatorial sputtering in phosphine gas. The films on both GaP and Si showed high crystalline quality, but the films grown on Si exhibited higher threading dislocation densities and antiphase domains compared to those on GaP. The results suggest the potential for high-quality epitaxial ZnGeP2 growth with optimization of synthesis conditions and substrate preparation.
CRYSTAL GROWTH & DESIGN
(2022)
Article
Chemistry, Physical
Xiaoman Zhang, Eric A. Stach, W. J. Meng, Andrew C. Meng
Summary: In this study, epitaxial wurtzite AlScN thin films were grown on Si (111) substrates by ultra-high vacuum reactive sputtering. Sc alloying in AlN enhances piezoelectricity and induces ferroelectricity, making epitaxial thin films suitable for systematic investigations of these materials. Increasing Sc concentration leads to crystalline disorder and a structural transition from wurtzite to rocksalt, as well as nanoscale compositional segregation consistent with spinodal decomposition. The observed composition fluctuations are correlated with polarization domains, suggesting an influence on ferroelectric properties. These results provide a route for creating single crystal AlScN films and self-assembled composition modulation.
NANOSCALE HORIZONS
(2023)
Article
Chemistry, Multidisciplinary
Ivan Yakovlev, Ivan Tarasov, Anna Lukyanenko, Mikhail Rautskii, Leonid Solovyov, Alexander Sukhachev, Mikhail Volochaev, Dmitriy Efimov, Aleksandr Goikhman, Ilya Bondarev, Sergey Varnakov, Sergei Ovchinnikov, Nikita Volkov, Anton Tarasov
Summary: In this study, Mn5Ge3 epitaxial thin films were successfully synthesized on Si(111) substrates by co-deposition of Mn and Ge. The highly ordered growth mode was stabilized by adjusting the evaporation rate of Mn and Ge. The lattice parameters of the films were close to the bulk values and exhibited two azimuthal crystallite orientations. A double buffer layer model was proposed to explain the elimination of lattice mismatch between Si and Mn5Ge3 film.
Article
Nanoscience & Nanotechnology
S. Xia, W. Zhang, Z. Yuan, J. Li, J. Ye, Y. Gu, Y. Miao, C. Li, Y. Deng, A. Shen, H. Lu, Y-F Chen
Summary: This study investigated the epitaxial growth of Si1-xGex thin films and observed a laminated relaxation process above a certain thickness, where the highly strained pseudomorphic layer could still be preserved even after relaxation. The anomalous relaxation phenomenon was attributed to a dislocation-driven relaxation mechanism, which could enhance the growth of highly mismatched heterostructure systems by manipulating dislocations.
MATERIALS TODAY NANO
(2021)
Article
Chemistry, Multidisciplinary
Inshad Jum'h, Husam H. Abu-Safe, Morgan E. Ware, I. A. Qattan, Ahmad Telfah, Carlos J. Tavares
Summary: This study investigates the surface atomic arrangement and physical properties of aluminum ultrathin layers deposited on c-Si(111)-7 x 7 and hydrogen-terminated c-Si(111)-1 x 1 surfaces using molecular beam epitaxy. X-ray photoelectron spectroscopy was used to determine the surface species, and 3D atomic force microscopy was used to investigate clustering formations in the film structure. Reflection high-energy electron diffraction experiments confirmed the surface crystalline structure of the c-Si(111) during the deposition of the aluminum layers. The surface electrical conductivity was tested against atmospheric oxidation, showing differences in conductivity based on the formation of various alloys on the surface.
Article
Nanoscience & Nanotechnology
Ping Wang, Ding Wang, Shubham Mondal, Yuanpeng Wu, Tao Ma, Zetian Mi
Summary: This study presents a unique approach, called interfacial modulated lattice-polarity-controlled epitaxy (IMLPCE), to overcome the challenges in achieving III-nitride heterostructures with controlled lattice-polarity on silicon substrates. It provides an alternative method for seamlessly integrating III-nitrides with mature Si-based device technology.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Physical
Avishek Banik, John Z. Tubbesing, Bin Luo, Xiaoting Zhang, Jay A. Switzer
Summary: The development of future optoelectronic materials relies on the high-performance p-type materials with optical transparency. Epitaxial growth of gamma-CuI on single crystalline Si(111) using a room-temperature electrochemical method demonstrates high in-plane and out-of-plane order. The deposition mechanism involves nucleating CuI seed crystals on n-Si(111) and simultaneous oxidation of Si to form SiOx, resulting in the lateral overgrowth of CuI seeds into a continuous film.
CHEMISTRY OF MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Harmanpreet Kaur Sandhu, John Wellington John, Alka Jakhar, Abhishek Sharma, Alok Jain, Samaresh Das
Summary: This study demonstrates a nanolayered MoSe2/GaN heterojunction photodetector that is capable of efficient broadband photodetection. Through experimental analysis and simulation verification, it is shown that the device exhibits high responsivity and detectivity, and the energy band structure and transport mechanism are thoroughly studied.
ADVANCED MATERIALS INTERFACES
(2022)
Article
Physics, Applied
Sudarshan Singh, Subhrajit Mukherjee, Samik Mukherjee, Simone Assali, Lu Luo, Samaresh Das, Oussama Moutanabbir, Samit K. Ray
Summary: A single nanowire photodetector with a high Sn-content Ge-Ge0.92Sn0.08 core-shell structure, grown by chemical vapor deposition, exhibits superior performance at the optical communication wavelength of 1.55 μm, showcasing the potential of GeSn nanowires for future Si-integrated infrared photonics.
APPLIED PHYSICS LETTERS
(2022)
Article
Nanoscience & Nanotechnology
Harmanpreet Kaur Sandhu, John Wellington John, Alka Jakhar, Abhishek Sharma, Alok Jain, Samaresh Das
Summary: This study demonstrates the fabrication of MoSe2/p-GaN heterostructure for light detection, exhibiting low noise broadband spectral response and high photocurrent to dark current ratio. The device achieves high responsivity and low noise equivalent power at an applied bias of 1 V, with fast rise/fall time.
Article
Chemistry, Multidisciplinary
Sumit Sharma, Akshay Moudgil, Sanjay Singh, Samaresh Das, Prashant Mishra
Summary: In this study, a highly responsive FET biosensor based on tungsten trioxide thin film is fabricated to detect the physiological concentration of total ammonia in human body fluids, serving as a prognostic marker for liver disorders. The device shows reliable and accurate results for ammonia sensing, with a high response towards ammonia in human plasma. It is also capable of real-time detection of very low concentrations of ammonia, demonstrating its potential for point-of-care applications.
ADVANCED MATERIALS INTERFACES
(2022)
Article
Optics
Julian Muenzberg, Franz Draxl, Saimon Filipe Covre da Silva, Yusuf Karli, Santanu Manna, Armando Rastelli, Gregor Weihs, Robert Keil
Summary: We report on a multi-photon source based on active demultiplexing of single photons emitted from a resonantly excited GaAs quantum dot. Active temporal-to-spatial mode demultiplexing is implemented via resonantly enhanced free-space electro-optic modulators, allowing for routing individual photons at a high switching rate of 38 MHz. The study demonstrates efficient routing into four spatial modes with an end-to-end efficiency of approximately 79% and measures a four-photon coincidence rate of 0.17 Hz, mainly limited by the brightness of the single-photon source rather than the efficiency of the demultiplexer itself. The demultiplexer is used to characterize the pairwise indistinguishability of consecutively emitted photons from the quantum dot with variable delay time.
Article
Engineering, Electrical & Electronic
John Wellington John, Veerendra Dhyani, Alka Jakhar, Harmanpreet Kaur Sandhu, Sheetal Dewan, Samit K. Ray, Samaresh Das
Summary: This study discusses a polarization-sensitive SWIR phototransistor based on black arsenic and germanium heterojunction, which exhibits high responsivity, high detectivity, fast response, and highly polarization sensitive photocurrent.
IEEE ELECTRON DEVICE LETTERS
(2022)
Article
Engineering, Electrical & Electronic
Sumit Sharma, Akshay Moudgil, Sanjay Singh, Prashant Mishra, Samaresh Das
Summary: This article demonstrates an ultrasensitive field-effect transistor (FET) for the detection of hydrogen sulfide (H2S) in human blood or plasma. The biosensor utilizes multiple layers of MoSe2 as the channel material and achieves detection of H2S at concentrations as low as 1 μM. With a wide linear dynamic range and low detection limit, this FET device is suitable for quick and real-time detection of H2S in plasma.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Vinit Kumar Yadav, Yogesh M. Patel, Supreet Singh Bahga, Samaresh Das, Dhiman Mallick
Summary: In this study, a cost-effective, scalable, and rapid technique for fabricating a robust and high-performance on-chip positive magnetophoretic system is demonstrated. The system combines a thick patterned permanent magnet and a microfluidic channel on a single PMMA substrate for on-chip manipulation of magnetic particles. The magnet pattern design exerts a spatially varying magnetic force on the particles in the channel, enabling capturing at specific locations. The device geometry is optimized using FEM simulations to prevent blockage and simplify fabrication. A 1.5-fold enhancement in trapping efficiency is observed at a lower flow rate of 9 μl/min, resulting in 94.5% trapping efficiency.
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
(2023)
Article
Chemistry, Multidisciplinary
Barbara Ursula Lehner, Tim Seidelmann, Gabriel Undeutsch, Christian Schimpf, Santanu Manna, Michal Gawelczyk, Saimon Filipe Covre da Silva, Xueyong Yuan, Sandra Stroj, Doris E. Reiter, Vollrath Martin Axt, Armando Rastelli
Summary: The study investigates the behavior of entangled photon pairs from quantum dots at elevated temperatures and finds degradation in entanglement as well as changes in decay dynamics. This research provides important insights for optimizing quantum dots as sources of highly entangled photons at higher temperatures.
Article
Nanoscience & Nanotechnology
Sheetal Dewan, Prabal Dweep Khanikar, Richa Mudgal, Avneet Singh, Pranaba Kishor Muduli, Rajendra Singh, Samaresh Das
Summary: This study presents the growth, characterization, and optoelectronic application of large-area, 2D germanium selenide (GeSe) layers using pulsed laser deposition (PLD). Phototransistors based on few-layered 2D GeSe on a SiO2/Si substrate were fabricated for ultrafast, low noise, and broadband light detection. The GeSe phototransistor exhibited high photoresponsivity, external quantum efficiency, specific detectivity, and ultralow noise equivalent power, with an ultrafast response time and photoresponse up to a high cut-off frequency. These promising features make PLD-grown GeSe layers a favorable choice for optoelectronic devices in the visible-to-infrared spectral range.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Physics, Applied
Pankaj Pathak, Vinit Kumar Yadav, Samaresh Das, Dhiman Mallick
Summary: In this study, an infrared-driven, Ni/lead magnesium niobate-lead titanate (PMN-PT) magnetoelectric (ME) heterostructure-based sensor was developed, enabling rapid assessment of suspended magnetic nanoparticles (MNPs) in a fluidic environment without the need for an external magnetic field. The device utilizes the optothermal-pyroelectric property of the PMN-PT layer to quantitatively assess the concentration of MNPs, showing different transient photocurrent responses against varied MNP concentrations with high sensitivity and fast response time. This ME device can greatly enhance the efficacy of current lab-on-a-chip systems for critical biomedical applications.
APPLIED PHYSICS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Shubham Saxena, Wasi Uddin, Sumit Sharma, Samaresh Das, V. Ramgopal Rao
Summary: Two-dimensional materials, such as tungsten diselenide (WSe2), possess unique properties and can have a tunable temperature coefficient of resistance (TCR) by manipulating the gate voltage. The TCR of WSe2 is approximately six times higher than that of molybdenum disulfide (MoS2) and 19 times higher than metallic thin films. The control of TCR in WSe2 can be achieved within a range of applied gate voltage, allowing for specific TCR values to be selected for various applications like bolometers, thermal sensors, and accelerometers.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Nanoscience & Nanotechnology
Nidhi, Samaresh Das, Tashi Nautiyal
Summary: This study investigates the optoelectronic properties of black arsenic and finds that they can be tuned through thickness control. The devices exhibit the best photoresponsivity and detectivity at specific thicknesses. These results suggest a promising application potential of black arsenic in future opto- and nanoelectronic devices.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Nanoscience & Nanotechnology
Himanshu Bangar, Akash Kumar, Niru Chowdhury, Richa Mudgal, Pankhuri Gupta, Ram Singh Yadav, Samaresh Das, Pranaba Kishor Muduli
Summary: The study reveals a high spin-to-charge conversion effect at the interface between TMD monolayers and ferromagnetic materials, providing new opportunities for the development of spintronic devices.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Engineering, Electrical & Electronic
Alka Jakhar, Dhairya Singh Arya, Suprovat Ghosh, Samaresh Das
Summary: This study reports a Dirac semimetal-platinum telluride (PtTe2)-based terahertz detector with a broadband response and improved performance.
IEEE SENSORS LETTERS
(2022)
