Article
Engineering, Electrical & Electronic
A. Azizur Rahman, Nirupam Hatui, Carina B. Maliakkal, Priti Gupta, Jayesh B. Parmar, Bhagyashree A. Chalke, Arnab Bhattacharya
Summary: The study found that the choice of nucleation layer significantly affects the properties of semipolar GaN epilayers. Direct growth of (112 over bar 2) GaN without buffer layers provided the best crystal quality and relatively enhanced near-band-edge photoluminescence emission.
JOURNAL OF ELECTRONIC MATERIALS
(2021)
Article
Crystallography
Xu-Qiang Shen, Kazutoshi Kojima
Summary: AlN films were grown on c-plane sapphire substrates by AFHT-MOCVD, and the effects of source gas flow rate and growth temperature on the AlN growth rate were studied. The maximum growth rate achieved was approximately 4.0 μm/hour. Possible mechanisms for gas reactions in the AFHT-MOCVD growth process were qualitatively discussed based on experimental results. The as-grown AlN films were characterized using HRXRD, SEM, and STEM, and exhibited narrow FWHM values for symmetric and asymmetric AlN diffractions, indicating the potential for high-quality growth using this technique.
JOURNAL OF CRYSTAL GROWTH
(2022)
Article
Crystallography
Moe Shimokawa, Shohei Teramura, Shunya Tanaka, Tomoya Omori, Kazuki Yamada, Yuya Ogino, Ayumu Yabutani, Sho Iwayama, Kosuke Sato, Motoaki Iwaya, Tetsuya Takeuchi, Satoshi Kamiyama, Isamu Akasaki, Hideto Miyake
Summary: In the growth of Al0.6Ga0.4N, the formation of loop dislocations during three-dimensional growth reduces the dislocation density effectively. The study found that the spontaneous nucleation behavior of Al0.6Ga0.4N strongly depends on the fabrication temperature of homo-AlN, leading to successful reduction of dislocation density to as low as 5.8 x 10(8) cm(-2).
JOURNAL OF CRYSTAL GROWTH
(2021)
Article
Crystallography
A. Maassdorf, D. Martin, H. Wenzel, A. Knigge, M. Weyers
Summary: This study focuses on achieving laser emission around 700 nm by using GaxIn1_xAsyP1_y material. By controlling the strain and thickness of the material, compressively strained GaxIn1_xAsyP1_y quantum wells with the desired wavelength have been successfully grown, and high power laser output has been achieved.
JOURNAL OF CRYSTAL GROWTH
(2023)
Article
Crystallography
Yun Lai, Ding Wang, Qinhao Kong, Xiaoju Luo, Jinfeng Tang, Rensuo Liu, Fei Hou, Xianying Wang, Troy J. Baker
Summary: Four-inch semi-insulating free-standing gallium nitride (GaN) wafers grown by hydride vapor phase epitaxy (HVPE) with carbon doping were obtained through a self-separated process. The as-grown wafer thickness can reach 900 mu m without cracks, and x-ray diffraction rocking curves show low FWHMs. The measured resistivity was greater than 10(10) Omega-cm.
JOURNAL OF CRYSTAL GROWTH
(2021)
Article
Chemistry, Physical
Nico Lovergine, Ilio Miccoli, Leander Tapfer, Paola Prete
Summary: The lattice tilt, mosaicity, and defect content of relaxed GaAs grown on exactly-oriented and 4 degrees-offcut (11 1)Si were investigated. Thin GaAs single-layers grown at 400°C and annealed at 700°C showed a density of surface pinholes. Double-layer samples were obtained by GaAs overgrowth at 700°C. The GaAs epilayers were tilted with respect to Si and rotational twins were observed in X-ray diffraction (XRD) pole figures.
APPLIED SURFACE SCIENCE
(2023)
Article
Crystallography
Patrick Haeuser, Christian Blumberg, Lisa Liborius, Werner Prost, Nils Weimann
Summary: This paper presents a study on position-defined Al-polar AlN nucleation for growing ordered Ga-polar GaN nanowire arrays, which could be used in future nanowire-based devices. By adjusting the placement pattern of Si-pillars, the collection area of Ga-adatoms per nanowire can be varied, allowing for control of wire size and pitch.
JOURNAL OF CRYSTAL GROWTH
(2021)
Article
Crystallography
C. R. Tait, S. R. Lee, J. Deitz, M. A. Rodriguez, D. L. Alliman, B. P. Gunning, G. M. Peake, A. Sandoval, N. R. Valdez, P. R. Sharps
Summary: Progress has been made in the synthesis of semimetal Cd3As2 by metal-organic chemical-vapor deposition (MOCVD), with optimized growth conditions revealing that InAs-terminated substrates yield the most desirable results. Advanced imaging techniques and x-ray diffraction modalities have been utilized to extensively study the microstructure of Cd3As2 thin films, showing smooth and specular surfaces with low roughness. The films exhibit strain relaxation and belong to the P4(2)/nbc space group, positioning MOCVD-grown Cd3As2 as a Dirac semimetal of interest for topological quantum materials research.
JOURNAL OF CRYSTAL GROWTH
(2021)
Article
Physics, Multidisciplinary
Paul Loubeyre, Florent Occelli, Paul Dumas
Summary: This study investigates the influence of nuclear quantum fluctuations on the properties of dense hydrogen, focusing on its potential metallization. Raman spectroscopy and synchrotron infrared absorption measurements are conducted on deuterium at 460 GPa and 80 K, revealing the isotopic effects on the electronic and vibrational properties in phase III. The findings also suggest a probable transition to metal deuterium, occurring at a shifted pressure compared to hydrogen, and are compared to advanced calculations quantifying the reduction of the band gap caused by nuclear quantum fluctuations.
PHYSICAL REVIEW LETTERS
(2022)
Article
Crystallography
Lin Zhang, Zeren Wang, Jiejun Wu, Tong Han, Fang Liu, Xingyu Zhu, Tongjun Yu
Summary: In this study, high quality semi-polar GaN layers were fabricated on m-plane sapphire templates using vertical hydride vapor phase epitaxy system. The in-plane epitaxial relationships between GaN and sapphire substrate were determined, and the crystalline anisotropies were shown to be associated with crystal quality and surface defects.
JOURNAL OF CRYSTAL GROWTH
(2022)
Article
Chemistry, Multidisciplinary
Seiya Shimono, Hiroki Ishibashi, Yusuke Nagayoshi, Hidekazu Ikeno, Shogo Kawaguchi, Masato Hagihala, Shuki Torii, Takashi Kamiyama, Katsuya Ichihashi, Sadafumi Nishihara, Katsuya Inoue, Yui Ishii, Yoshiki Kubota
Summary: A structural transition from a cubic phase to a tetragonal phase was observed in non-centrosymmetric oxyfluoride Co3Sb4O6F6 at around 180K. The transition was confirmed through specific heat, magnetization, and dielectric measurements, and a magnetic structure analysis revealed a transition from a paramagnetic phase to a G-type antiferromagnetic phase at around 67K.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(2022)
Article
Chemistry, Physical
Yuji Ikeda, Tanja S. Lehmann, Marc Widenmeyer, Mauro Coduri, Blazej Grabowski, Rainer Niewa
Summary: This study revisits the crystal structure and phase stability of Co2N using experiments and first-principles calculations, confirming the stable crystal structure of Co2N as an isotype of eta-Fe2C and Co2C with the space group Pnnm. The research also highlights the importance of considering strong electron correlation in transition metal nitrides for predicting correct experimental structures and magnetic states, with an effective value of U-eff = 2.75 eV identified for Co2N.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Multidisciplinary
Hua-Chiang Wen, Ssu-Kuan Wu, Cheng-Wei Liu, Jin-Ji Dai, Wu-Ching Chou
Summary: The nanotribological properties of AlxGa1-xN epitaxial films grown on low-temperature-grown GaN/AlN/Si substrates were investigated. It was found that the Al compositions played a crucial role in determining the strength of bonding forces and shear resistance. The measured friction coefficient (mu) values decreased with increasing Al compositions, indicating a transition from brittleness to ductility in the AlxGa1-xN system.
Article
Physics, Applied
J. S. Cabaco, D. N. D. Faye, J. P. Araujo, E. Alves, S. Magalhaes
Summary: In this study, high quality AlGaN layers grown on a commercial c-sapphire substrate were implanted with Ar+ ions at varying energies to investigate the strain field created at different penetration depths. Simulation and experimental results showed significant differences in strain distribution at different depths under various implantation conditions.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Multidisciplinary Sciences
Ulrich Burkhardt, Aimo Winkelmann, Horst Borrmann, Andreea Dumitriu, Markus Koenig, Grzegorz Cios, Yuri Grin
Summary: This study investigates the assignment of enantiomorphs using diffraction methods for X-rays and electrons. By comparing experimental and simulated Kikuchi patterns, enantiomorphs in polycrystalline materials of beta-Mn and Pt2Cu3B can be accurately determined.
Article
Nanoscience & Nanotechnology
Filip Hjort, Johannes Enslin, Munise Cobet, Michael A. Bergmann, Johan Gustavsson, Tim Kolbe, Arne Knauer, Felix Nippert, Ines Hausler, Markus R. Wagner, Tim Wernicke, Michael Kneissl, Asa Haglund
Summary: This study successfully demonstrates an optically pumped VCSEL emitting in the UVB spectrum at room temperature, providing a new technology for ultraviolet light sources applications.
Article
Physics, Applied
Douglas Cameron, Paul R. Edwards, Frank Mehnke, Gunnar Kusch, Luca Sulmoni, Marcel Schilling, Tim Wernicke, Michael Kneissl, Robert W. Martin
Summary: During the epitaxy of AlGaN on sapphire for deep UV emitters, significant lattice mismatch causes highly strained heterojunctions and threading dislocations, which permeate through the UVC LED heterostructure, perturb the local environment, and encourage high point defect densities and three-dimensional growth. These point defects can create parasitic recombination pathways and compensate intentional dopants.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Applied
Nan Hu, Geoffrey Avit, Markus Pristovsek, Yoshio Honda, Hiroshi Amano
Summary: We investigated the incorporation of indium into InGaN/GaN quantum wells grown by metal-organic vapor phase epitaxy by varying the flows of gallium and indium precursors on different orientations. X-ray diffraction analysis was used to correlate the layer thickness and indium composition with a model based on indium and gallium incorporation efficiencies. The results showed that the indium incorporation efficiency is linked to the Langmuir surface coverage of gallium, indicating a preference for incorporating indium atoms close to gallium atoms.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Applied
Shiki Tanaka, Ryota Ishii, Norman Susilo, Tim Wernicke, Michael Kneissl, Mitsuru Funato, Yoichi Kawakami
Summary: The study investigates the radiative recombination efficiency of AlGaN quantum wells under different excitation conditions using picosecond-laser-excited photoluminescence spectroscopy. It was found that at low temperature, the PL efficiency equals the RRE, but at room temperature, the PL efficiency is lower under non-selective excitation conditions.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Markus Pristovsek
Summary: This article presents a method for directly obtaining the maximum internal quantum efficiency (IQE) of light-emitting diodes (LEDs) from experimental data without the need for fitting. This method also allows for the observation of changes in the A, B, or C parameters over the current range.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2023)
Article
Engineering, Electrical & Electronic
H. K. Cho, A. Mogilatenko, N. Susilo, I Ostermay, S. Seifert, T. Wernicke, M. Kneissl, S. Einfeldt
Summary: In this study, the formation of ohmic contacts between V/Al/Ni/Au metal stacks and n-Al0.65Ga0.35N:Si was investigated. The influence of Au metal thickness and annealing temperature on the formation of ohmic contacts was analyzed. The results showed that a low contact resistivity and smooth surface ohmic contact could be achieved at a low annealing temperature of 750 degrees C with V(15 nm)/Al(120 nm)/Ni(20 nm)/Au(40 nm) combination. The formation of two thin interfacial regions consisting of AlN and an Au-rich phase played a crucial role in achieving low contact resistivity.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2022)
Article
Physics, Applied
A. Knauer, T. Kolbe, S. Hagedorn, J. Hoepfner, M. Guttmann, H. K. Cho, J. Rass, J. Ruschel, S. Einfeldt, M. Kneissl, M. Weyers
Summary: High temperature annealed AlN/sapphire templates have a smaller in-plane lattice constant compared to conventional non-annealed AlN/sapphire templates grown by MOVPE. This results in additional lattice mismatch between the template and the AlGaN-based UVC LED heterostructure. The mismatch introduces compressive strain in AlGaN quantum wells, leading to enhanced transverse electric polarization of the quantum well emission below 235 nm.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Wentao Cai, Jia Wang, Jeong-Hwan Park, Yuta Furusawa, Heajeong Cheong, Shugo Nitta, Yoshio Honda, Markus Pristovsek, Hiroshi Amano
Summary: We presented nanoplatelet In (x) Ga1-x N pseudosubstrates with varying In content on low-dislocation-density GaN substrates. These nanoplatelets effectively relaxed in-plane strain and allowed for the use of a thick active layer to reduce built-in polarization. The 15 nm thick InGaN active layers grown on these nanoplatelets exhibited a remarkable cathodoluminescence redshift, suggesting enhanced In incorporation efficiency in InGaN nanoplatelets with higher In content. Moreover, the sample emitting at 617 nm showed a negligible blueshift under excitation-power-dependent photoluminescence, indicating a weak polarization field introduced by the high-In-content pseudosubstrates and thick active layer.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Crystallography
Markus Pristovsek
Summary: The article discusses the growth of wurtzite AlPyN1-y and Al1-xGaxPyN1-y on GaN using Metal-Organic Vapour Phase Epitaxy, emphasizing the importance of parameters such as temperature and gas phase ratio to avoid issues like unintentional doping.
JOURNAL OF CRYSTAL GROWTH
(2022)
Article
Physics, Applied
F. Piva, M. Pilati, M. Buffolo, N. Roccato, N. Susilo, D. Hauer Vidal, A. Muhin, L. Sulmoni, T. Wernicke, M. Kneissl, C. De Santi, G. Meneghesso, E. Zanoni, M. Meneghini
Summary: This paper investigates the degradation of deep-ultraviolet LEDs and provides new insights through the combination of C-DLTS, electro-optical characterization, and simulations. The C-DLTS measurements identify three traps, two of which are associated with Mg-related defects also detected in the unaged device, and one related to point defects generated during the ageing procedure. Furthermore, the forward I-V variation is explained by the degradation of the p-contact due to Mg passivation based on the obtained results and TCAD simulations. The optical degradation is attributed to the increase in defectiveness in the active region and surrounding areas, leading to a decrease in injection efficiency, an increase in non-radiative recombination, and an increase in trap-assisted tunneling processes.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Tim Kolbe, Arne Knauer, Jens Rass, Hyun Kyong Cho, Sylvia Hagedorn, Fedir Bilchenko, Anton Muhin, Jan Ruschel, Michael Kneissl, Sven Einfeldt, Markus Weyers
Summary: This study compares far-ultraviolet-C (far-UVC) light-emitting diodes (LEDs) with a wavelength of 234 nm with different polarization-doped AlGaN hole injection layers (HILs) in terms of their emission power, voltage, and leakage current. The thickness of the polarization-doped layer (PDL), additional Mg doping, and the combination of PDL with conventionally Mg-doped AlGaN HIL are discussed. The results show that the thickness of PDL has little influence on power and voltage, but increasing thickness reduces leakage current. Additional Mg doping significantly decreases emission power. Combining PDL with conventionally Mg-doped AlGaN HIL has similar power and voltage, but increased leakage current. Polarization doping improves the performance of far-UVC LEDs compared to conventionally Mg-doped p-side LEDs.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Yingying Lin, Hadi Sena, Martin Frentrup, Markus Pristovsek, Yoshio Honda, Hiroshi Amano
Summary: The stress relaxation of Al0.19Ga0.81N grown by metal-organic vapor phase epitaxy on quasi-bulk GaN substrates was studied using x-ray diffraction. The anisotropic in-plane stress caused orthorhombic distortion of the lattice. A mathematical method was developed to calculate the distortion along different directions and obtained the lattice parameters, Al content, and strain values. The stress relaxation in the two in-plane directions involved different mechanisms, with misfit dislocations and crack formation being the dominant methods of relaxation.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Jeong-Hwan Park, Markus Pristovsek, Wentao Cai, Heajeong Cheong, Atsushi Tanaka, Yuta Furusawa, Dong-Pyo Han, Tae-Yeon Seong, Hiroshi Amano
Summary: In this study, the impact of sidewall conditions on the performance of micro-light emitting diodes (mu LEDs) was investigated. It was found that inductively coupled plasma-reactive ion etching (ICP-RIE) caused surface damages to the sidewall, and tetramethylammonium hydroxide (TMAH) treatment eliminated the etching damage and flattened the sidewall surface. The size dependence of the external quantum efficiency (EQE) of mu LEDs was explained in terms of non-radiative recombination rate and light extraction.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Valentin Jmerik, Dmitrii Nechaev, Alexey Semenov, Eugenii Evropeitsev, Tatiana Shubina, Alexey Toropov, Maria Yagovkina, Prokhor Alekseev, Bogdan Borodin, Kseniya Orekhova, Vladimir Kozlovsky, Mikhail Zverev, Nikita Gamov, Tao Wang, Xinqiang Wang, Markus Pristovsek, Hiroshi Amano, Sergey Ivanov
Summary: This article discusses the use of GaN/AlN heterostructures for ultraviolet-C (UVC) emitters, employing multiple two-dimensional (2D) quantum disk/quantum well structures with varying GaN nominal thicknesses and AlN barrier layers. The growth process involved plasma-assisted molecular-beam epitaxy on c-sapphire substrates with a wide range of gallium and activated nitrogen flux ratios. By adjusting the Ga/N-2* ratio, the 2D-topography of the structures could be modified, leading to a variation in emission energy (wavelength). Electron-beam pumping was used to achieve high output optical power for different wavelength structures.
Article
Crystallography
Markus Pristovsek, Itsuki Furuhashi, Pietro Pampili
Summary: We investigated the growth of N-polar GaN on different misoriented (0001) sapphire substrates using metal-organic vapor phase epitaxy (MOVPE). The NH3 flow was found to be a key parameter affecting various properties of the growth, including roughness, growth rate, crystal quality, and impurities. Most parameters exhibited a reversal at a V/III ratio of approximately 500, either reaching a maximum or a minimum, indicating a change from a Ga-terminated Ga-adlayer surface to a N-terminated 3N-H (2 x 2) surface. Smooth N-polar GaN films could be achieved at extremely low V/III ratios, but maintaining good crystalline quality, low oxygen impurities, and smooth surfaces at low misorientations proved to be challenging.
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)
