Article
Chemistry, Physical
Piotr Tatarczak, Henryk Turski, Krzysztof P. Korona, Ewa Grzanka, Czeslaw Skierbiszewski, Andrzej Wysmolek
Summary: Detailed comparison of optical quality of GaN layers grown homoepitaxially on bulk Ga-polar and N-polar substrates by plasma-assisted molecular beam epitaxy was conducted. Layers grown on N-polar substrates showed one order of magnitude lower photo-luminescence intensity and decay time due to gallium-rich conditions, while nitrogen-rich growth conditions greatly improved the optical quality by suppressing formation of nitrogen vacancy-related point defects. Layers grown on N-polar substrates achieved linewidth below 1 meV and lifetime above 0.1 ns at He temperature.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Physical
Henryk Turski, Pawel Wolny, Mikolaj Chlipala, Marta Sawicka, Anna Reszka, Pawel Kempisty, Leszek Konczewicz, Grzegorz Muziol, Marcin Siekacz, Czeslaw Skierbiszewski
Summary: Atomically thin metal adlayers are used as surfactants in semiconductor crystal growth, with the role of the adlayer in dopant incorporation in GaN being unexplored. Experimental study shows that the presence of atomically thin gallium or indium layers dramatically affects Ge incorporation in GaN, with indium surfactant layer promoting Ge incorporation while gallium surfactant layer promotes segregation of Ge to the surface. Understanding the role of surfactants is crucial for controlling GaN doping and achieving high n-type doping levels using Ge.
Article
Materials Science, Multidisciplinary
I Ohkubo, Z. Hou, J. N. Lee, T. Aizawa, M. Lippmaa, T. Chikyow, K. Tsuda, T. Mori
Summary: The closed-loop optimization of epitaxial titanium nitride thin-film growth was achieved using metal-organic molecular beam epitaxy (MO-MBE) technique combined with Bayesian machine learning, reducing the number of growth experiments. Epitaxial TiN thin films grown under the optimized conditions exhibited abrupt superconductor transitions above 5 K, showing a new efficient approach for developing less-studied materials. The combination of thin-film growth technique and Bayesian approach is expected to accelerate the development of automated operation of thin-film growth apparatuses.
MATERIALS TODAY PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Nutthapong Discharoen, Sakuntam Sanorpim, Noppadon Nuntawong, Visittapong Yordsri, Suphakan Kijamnajsuk, Kentaro Onabe
Summary: Cubic AlN films were successfully grown on MgO substrates using a two-step cubic GaN buffer layer. The two-step buffer layer was found to play a crucial role in the epitaxial growth of c-AlN, resulting in improved crystallinity compared to one-step and nonGaN buffer layers.
Article
Energy & Fuels
Arto Aho, Riku Isoaho, Marianna Raappana, Timo Aho, Elina Anttola, Jari Lyytikainen, Arttu Hietalahti, Ville Polojarvi, Antti Tukiainen, Jarno Reuna, Leo Peltomaa, Mircea Guina
Summary: This article discusses the progress in developing lattice-matched GaAs-based solar cells with a focus on expanding the spectral coverage range, by assessing the performance of a four-junction solar cell to explore possibilities for further efficiency improvements, and demonstrating the integration of materials like AlGaInP and GaInNAsSb to achieve higher efficiencies in solar cells.
PROGRESS IN PHOTOVOLTAICS
(2021)
Article
Nanoscience & Nanotechnology
Bruno Daudin, Alexandra-Madalina Siladie, Marion Gruart, Martien den Hertog, Catherine Bougerol, Benedikt Haas, Jean-Luc Rouviere, Eric Robin, Maria-Jose Recio-Carretero, Nuria Garro, Ana Cros
Summary: The spontaneous growth of GaN nanowires in the absence of catalyst is controlled by Ga flux, with diffusion barriers causing an uneven distribution of Ga adatoms at the top surface leading to GaN accumulation in the periphery. This promotes the formation of superlattices in InGaN and AlGaN nanowires, while the presence of Mg enhances Al diffusion length along the sidewalls in AlN nanowires, inducing the formation of AlN nanotubes.
Article
Energy & Fuels
Janne Puustinen, Joonas Hilska, Arto Aho, Esperanza Luna, Antti Fihlman, Mircea Guina
Summary: The development of low bandgap GaAsNBi solar cells grown using MBE is reported, and the As/Ga flux ratio is found to play an important role in controlling the solar cell performance.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2024)
Article
Energy & Fuels
Riku Isoaho, Antti Tukiainen, Juuso Puutio, Arttu Hietalahti, Jarno Reuna, Antti Fihlman, Elina Anttola, Miika Keranen, Arto Aho, Mircea Guina
Summary: This study reports a comprehensive optimization process for GaInNAsSb solar cells grown by molecular beam epitaxy. The results show that the quantum efficiency and current generation of narrow gap materials can be significantly improved by increasing the growth temperature and reducing the As/III beam equivalent pressure ratio. It is also found that increasing the Sb flux can improve the material quality and inhibit phase separation.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2022)
Article
Chemistry, Physical
Mateusz Hajdel, Mikolaj Chlipala, Marcin Siekacz, Henryk Turski, Pawel Wolny, Krzesimir Nowakowski-Szkudlarek, Anna Feduniewicz-Zmuda, Czeslaw Skierbiszewski, Grzegorz Muziol
Summary: The design of the active region is crucial for III-nitride based LEDs due to carrier separation caused by built-in polarization. In this study, radiative transitions in InGaN-based LEDs with different quantum well thicknesses were investigated. The results showed that the thickness of the quantum well influenced the emission spectra, with thicker quantum wells exhibiting stable emission. The variation in emission spectra was attributed to differences in carrier density and the magnitude of built-in field screening. Excited states played a significant role in carrier recombination, except for the thinnest quantum well.
Article
Crystallography
Ana Bengoechea-Encabo, Steven Albert, Michael Niehle, Achim Trampert, Enrique Calleja
Summary: Two different arrays of GaN nanocolumns with different average diameters were selectively grown on GaN-buffered Si(0 0 1) substrates. The footprint of the nanocolumns plays an important role in the crystalline quality, despite the low quality of the GaN buffer layer. These results are significant for the integration of GaN-based nano-devices with conventional Si(0 0 1) electronics platform.
JOURNAL OF CRYSTAL GROWTH
(2023)
Article
Energy & Fuels
Riku Isoaho, Timo Aho, Arto Aho, Antti Tukiainen, Jarno Reuna, Marianna Raappana, Mircea Guina
Summary: Low-bandgap GaInNAsSb single junction solar cells with a planar Au back surface reflector exhibit high short-circuit current density and external quantum efficiency, showing potential for future applications in multijunction solar cells.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2022)
Article
Chemistry, Multidisciplinary
Anatoly Dvurechenskii, Aleksey Kacyuba, Gennadiy N. Kamaev, Vladimir A. Volodin, Zhanna Smagina
Summary: The radiation-induced phenomena during CaSi2 crystal growth were investigated in the epitaxial CaF2 growth process on Si (111) and after film formation with electron irradiation on Si (111). Both approaches lead to the formation of CaSi2 crystals in the irradiated region of the CaF2 film.
Article
Chemistry, Multidisciplinary
Isao Ohkubo, Takashi Aizawa, Katsumitsu Nakamura, Takao Mori
Summary: The study found that using thin-film technology can control phase formation, which is advantageous for the preparation of undeveloped materials. To obtain thin films with desired properties, it is necessary to control factors such as crystal orientation, quality, and defect concentration in the thin films. Tuning the competition between thermodynamics and kinetics during vapor-phase thin-film growth is crucial for successfully fabricating high-quality thin films.
FRONTIERS IN CHEMISTRY
(2021)
Article
Nanoscience & Nanotechnology
T. Auzelle, M. Oliva, P. John, M. Ramsteiner, A. Trampert, L. Geelhaar, O. Brandt
Summary: The self-assembly of GaN nanowires on TiN(111) substrates is examined using SiN x patches as nucleation seeds. The density of the nanowires can be tuned by three orders of magnitude by varying the amount of pre-deposited SiN x , bridging the density regimes achievable by direct self-assembly with MBE or MOVPE. This approach has potential applications in tuning the density of III-V semiconductors grown on inert surfaces like 2D materials.
Article
Physics, Applied
Masahiro Okujima, Kohei Yoshikawa, Shota Mori, Mitsuki Yukimune, Robert D. Richards, Bin Zhang, Weimin M. Chen, Irina A. Buyanova, Fumitaro Ishikawa
Summary: GaAs/GaNAsBi/GaAs core-multishell nanowires were successfully grown on Si(111) substrates, with a GaNAsBi shell containing N and Bi and having a compressive lattice mismatch of less than 0.2%, resulting in room-temperature photoluminescence at around 1300 nm.
APPLIED PHYSICS EXPRESS
(2021)
Article
Crystallography
Jianzheng Hu, Long Yan, Ning Zhou, Yao Chen, Xiaoni Yang, Lianqiao Yang, Shiping Guo
Summary: The effect and mechanism of carrier gas velocity, V/III ratio, and carrier gas velocity match on the growth rate of AlN were investigated in this study. The results showed that the growth rate of AlN initially increased with hydrogen flow rate, reached saturation, and then decreased monotonically. The turning point value depended on the equipment and process. By increasing the MO VM, the growth rate of AlN could be improved, but the uniformity deteriorated due to turbulence and loss of uniform boundary layer. High quality AlN films were successfully grown on nano-patterned sapphire substrates with improved crystalline quality and atomic smooth surfaces.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Tingting Ma, Yang Li, Kangning Sun, Qinglin Cheng, Sen Li
Summary: This study investigates the melting process and nucleation behavior of sodium crystals using molecular dynamics simulation. The results show good agreement between simulated and experimental values for the melting temperature, density, and radial distribution function of sodium. The diffusion coefficient of liquid sodium increases linearly with temperature, and the homogeneous nucleation rate of melting in superheated sodium crystal exponentially increases with temperature. The findings provide theoretical support for applications involving heat and mass transfer in sodium-related systems.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Hisato Nishii, Shintarou Iida, Akira Yamasaki, Takumi Ikenoue, Masao Miyake, Toshiya Doi, Tetsuji Hirato
Summary: Epitaxial V2O3 films were fabricated on sapphire substrates using mist chemical vapor deposition (mist CVD) method, eliminating the need for high vacuum conditions. The films can be grown on sapphire substrates even under atmospheric pressure, with the optimal growth temperature at 823 K. The films grown at 823 K exhibit a metal-insulator transition at approximately 155 K. The film on C-plane sapphire exhibits a lower transition temperature compared to those on R- and A-plane sapphire substrates.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Jani Jesenovec, Kevin Zawilski, Peter Alison, Stephan J. Meschter, Sambit K. Saha, Andrew J. Sepelak, Peter G. Schunemann
Summary: In this study, NiSb needles were successfully formed in InSb by manipulating the growth rate and adding NiSb. These needle structures in InSb can be used to tune the magnetoresistance of devices. Additionally, undoped InSb crystals demonstrated good infrared transmission at low growth rates.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
D. Joseph Daniel, P. Karuppasamy, H. J. Kim
Summary: The 2-amino 4-methyl pyridinium oxalate (2A4MPO) compound was synthesized and its crystal structure, functional groups, thermal stability, electrical properties, and third-order nonlinear optical properties were studied. The results demonstrate that the synthesized crystal has good structural integrity, thermal stability, and potential for third-order nonlinear optical applications.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
C. W. Lan
Summary: The past two decades have witnessed a significant transformation in solar silicon crystal growth, especially in the competition between multi-crystalline silicon (Multi-Si) and mono-crystalline silicon (Mono-Si). The demand for this crucial material has exponentially surged, with silicon solar panels capturing over 95% of the global PV market share. The advancements in crystal growth technology during this period have set historical benchmarks, with the market share shifting from high-performance multi-crystalline silicon (HPM-Si) to CZ silicon.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Peiyao Hao, Lili Zheng, Hui Zhang
Summary: A novel design of argon gas tube for removing impurities during silicon ingot growth was developed, and numerical simulations showed that it can effectively extract SiO.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Geetika Sahu, Chanchal Chakraborty, Subhadeep Roy, Souri Banerjee
Summary: This article discusses the novel fractal nature of hydrothermally synthesized MoS2 QDs. By adjusting the reaction time, the study found that the average size of QDs increases and then decreases with longer reaction times. STEM images indicate that shorter reaction times lead to sheet formation, while extended reaction times cause sheets to fragment into QDs.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Pengjian Lu, Wei Huang, Junjun Wang, Haitao Yang, Shiyue Guo, Bin Li, Ting Wang, Chitengfei Zhang, Rong Tu, Song Zhang
Summary: A systematic study on the tetramethylsilane-hydorgen (TMS-H-2) system for the deposition of pure single-crystal SiC by high-temperature chemical vapor deposition (HTCVD) method is conducted. The study investigates the effect of temperature, pressure, and H-2:TMS ratio on the deposition conditions and provides a theoretical basis and guidance for improving the quality and cost of industrial production of single-crystal SiC.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Xinyu Jiang, Liangliang Liu, Yanqing Liu, Yan Wang, Zhaoping Hou
Summary: Investigation on the preparation of anisometric templated textured high entropy or multi-element doped ferroelectric ceramics was conducted using A-site disordered niobate microcrystals. The effects of process parameters on the morphology and chemical composition were studied, and the photocatalytic properties of the microcrystals were evaluated.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Mobashsara Tabassum, Md. Ashraful Alam, Sabrina Mostofa, Raton Kumar Bishwas, Debasish Sarkar, Shirin Akter Jahan
Summary: In this study, high crystallinity copper nanoparticles were synthesized by altering the reaction medium at low temperatures. The results show that changing the reaction medium can reduce the surface energy of precursors and promote the formation of highly crystalline copper nanoparticles.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Ivan Bodnar, Vitaly V. Khoroshko, Veronika A. Yashchuk, Valery F. Gremenok, Mohsin Kazi, Mayeen U. Khandaker, Tatiana I. Zubar, Daria I. Tishkevich, Alex Trukhanov, Sergei Trukhanov
Summary: This work presents the production of single crystals of Cu2ZnGeSe4, a semiconducting quaternary compound, using a gas chemical method with iodine as a transporter. The phase state, crystal structure, and lattice constants of the synthesized samples were refined and determined. The band gap of Cu2ZnGeSe4 was calculated using transmission spectrum and it was found that the band gap increases by 12% with decreasing temperature in the range of 20-300 K.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Timur Malin, Igor Osinnykh, Vladimir Mansurov, Dmitriy Protasov, Sergey Ponomarev, Denis Milakhin, Konstantin Zhuravlev
Summary: The effect of growth temperature on the buffer leakage currents of GaN-on-Si layers was investigated. It was found that higher growth temperature results in lower leakage currents. The defects in GaN layers grown at different temperatures were studied using photoluminescence technique, and a correlation between leakage currents, structural perfection, and donor concentration in GaN-on-Si layers was established. It was also observed that reduced growth temperature leads to the formation of inversion domains.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Thi-Hoai-Thu Nguyen, Jyh-Chen Chen
Summary: The effect of heater power control on heat, flow, and oxygen transport for CCz crystal growth was studied. Shorter upper side heater design could improve crystal quality and growth, but with higher power consumption.
JOURNAL OF CRYSTAL GROWTH
(2024)
Article
Crystallography
Peter Rudolph
Summary: This article presents an overview of selected contributions to the development of crystal growth technology by the Laudise Prize awardee 2023. It discusses various aspects such as shaped crystal growth, the correlation between melt structure and crystal quality, control of intrinsic defects and inclusions, prevention of dislocation cell patterns, and melt growth experiments under a travelling magnetic field.
JOURNAL OF CRYSTAL GROWTH
(2024)