Article
Chemistry, Physical
Tomasz Sochacki, Robert Kucharski, Karolina Grabianska, Jan L. L. Weyher, Magdalena A. A. Zajac, Malgorzata Iwinska, Lutz Kirste, Michal Bockowski
Summary: A detailed analysis was conducted on the morphology of gallium nitride crystal growth obtained by ammonothermal and halide vapor phase epitaxy methods. The study aimed to determine the source of triangular planar defects visible in X-ray topography as areas with locally different lattice parameters. It was found that these defects are related to growth hillocks, and particular attention was paid to analyzing the merging of hillocks and its consequences. The nature and cause of these defects were determined, with the angle formed between adjacent hillocks being identified as a key factor.
Article
Chemistry, Physical
Saskia Schimmel, Michael Salamon, Daisuke Tomida, Steffen Neumeier, Tohru Ishiguro, Yoshio Honda, Shigefusa F. Chichibu, Hiroshi Amano
Summary: An in situ monitoring technique for tracking mass transport of the nitride in the ammonothermal method was evaluated using high-energy computed tomography. Suitable transparency in the autoclave volume can be achieved in a lab-scale setup for GaN crystal growth. For ammonoacidic growth, shorter scan durations or lower acceleration voltages are feasible.
Article
Physics, Applied
Kouhei Kurimoto, Quanxi Bao, Yutaka Mikawa, Kohei Shima, Toru Ishiguro, Shigefusa F. Chichibu
Summary: This study demonstrates the seeded growth of 2-inch-diameter GaN crystals via low-pressure acidic ammonothermal method. The grown crystals exhibit high lattice coherency and nearly bowing- and mosaic-free features, with superior photoluminescence properties. A large-size, nearly bowing-free GaN crystal was successfully obtained.
APPLIED PHYSICS EXPRESS
(2022)
Article
Crystallography
Lei Xu, Tengkun Li, Guoqiang Ren, Xujun Su, Xiaodong Gao, Shunan Zheng, Haixiao Wang, Ke Xu
Summary: The lateral growth in the a-direction is an effective method to expand the crystal size in basic ammonothermal GaN growth. Different stress distributions and optical properties were found among distinct regions, along with varying impurity concentrations. The findings indicate a small stress variation among interfaces and suggest the evolution process of lateral crystal growth.
JOURNAL OF CRYSTAL GROWTH
(2021)
Article
Crystallography
Tadao Hashimoto, Daryl Key, Edward Letts, Mathew Gaddy, Austin Gregory, James Dickens, Tim West, Wei Zhao, Mengzhe Guo, Temel Buyuklimanli
Summary: The resistivities of Mn-doped GaN crystals grown by the NEAT method were evaluated. C-plane Mn-doped GaN wafers were produced by grinding off an undoped seed crystal. Mn concentrations ranged from 7 x 1017 to 1.2 x 1019 cm^3. Secondary ion mass spectroscopy (SIMS) was used to measure Mn concentrations and other impurities.
JOURNAL OF CRYSTAL GROWTH
(2023)
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
Saskia Schimmel, Daisuke Tomida, Tohru Ishiguro, Yoshio Honda, Shigefusa E. F. Chichibu, Hiroshi Amano
Summary: The ammonothermal method is investigated as a promising technology for scalable production of GaN single crystals. The study focuses on the etch-back and growth conditions, as well as the transition between them. Numerical and experimental analyses show temperature differences and fluctuations during the transition, which affect the deposition of GaN on the crystals. The results provide insights into the crystal growth process and the optimization of production conditions.
Article
Crystallography
Tadao Hashimoto, Edward R. Letts, Daryl Key
Summary: This paper reviews the near-equilibrium ammonothermal (NEAT) growth of bulk gallium nitride (GaN) crystals, and evaluates the quality of 2 '' GaN substrates and 100 mm bulk GaN crystal grown in a pilot production reactor. Oxygen reduction advancements have led to lower residual oxygen, coloration, and optical absorption in NEAT GaN substrates. X-ray diffraction rocking curve maps confirmed high-quality and uniform microstructure across the entire surface of the crystals and substrates, with a significant reduction in dislocation density during NEAT growth.
Review
Crystallography
Saskia Schimmel, Daisuke Tomida, Tohru Ishiguro, Yoshio Honda, Shigefusa Chichibu, Hiroshi Amano
Summary: Numerical simulations play a crucial role in the design and optimization of crystal growth processes, especially for ammonothermal growth of bulk GaN where technical limitations in experimental investigations and accessing internal parameters exist. Factors such as fluid flow, thermal boundary conditions, and uncertainty in fluid properties under specific conditions are key considerations for developing accurate numerical models. A closer integration of numerical modeling, physical modeling, and measurements under ammonothermal process conditions is necessary to improve the accuracy of simulations.
Article
Materials Science, Multidisciplinary
Hande Ozcan, Daniel Salas, Ji Ma, Yang Ren, Yuriy I. Chumlyakov, Ibrahim Karaman
Summary: Single crystalline materials can exhibit superior performance due to the absence of grain boundaries, but controlling the crystallographic orientation is crucial for their applications. This study presents a new crystal reorientation mechanism that allows abrupt and massive orientation changes in bulk single crystalline and oligocrystalline alloys through solid state thermal processing. The findings provide a new strategy for manipulating the orientation of large single crystals to utilize their superior and highly anisotropic properties.
Article
Crystallography
Peter Becker, Rainer Niewa
Summary: Novel synthesis conditions were tested for the ammonothermal synthesis of InN single crystals. Successful synthesis of InN was achieved using appropriate reactants and mineralizers under mild reaction conditions. Information on the relative solubilities of the reactants in ammonia was obtained, providing insights into the reaction mechanism.
JOURNAL OF CRYSTAL GROWTH
(2022)
Article
Physics, Applied
Zhiwen Liang, Ye Yuan, Pengwei Wang, JunJie Kang, Qi Wang, Guoyi Zhang
Summary: This study comprehensively investigated the ex situ sputtered AlN buffer and GaN epilayer grown by metalorganic chemical vapor deposition. The study revealed that the AlN buffer deposited by sputtering technique could be oxidized in the atmosphere, which significantly affected the characteristics of the GaN epilayer. This finding has important guiding significance for the growth of high-quality III-nitride materials.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Crystallography
Akira Uedono, Junichi Takino, Tomoaki Sumi, Yoshio Okayama, Masayuki Imanishi, Shoji Ishibashi, Yusuke Mori
Summary: Defects in bulk GaN grown by the oxide vapor phase epitaxy method were investigated using positron annihilation spectroscopy. The study revealed that the major defect species in OVPE-GaN were Ga vacancy-type defects coupled with oxygen atoms, attributed to the high oxygen concentration during growth. A correlation between defect complexes and sample transparencies was observed. Additionally, an epitaxial film grown on OVPE-GaN was found to have a low vacancy concentration, indicating that epitaxial layers can be grown without being influenced by vacancies in the substrates.
JOURNAL OF CRYSTAL GROWTH
(2021)
Article
Chemistry, Physical
Guoqing Shao, Juan Wang, Shumiao Zhang, Yanfeng Wang, Wei Wang, Hong-Xing Wang
Summary: The study conducted homoepitaxial growth of step-flow single crystal diamond using a microwave plasma chemical vapor deposition system on a high-pressure high-temperature diamond substrate. The research focused on the surface morphology evolution, crystal quality, and growth mechanism of diamond, revealing the inhomogeneity in crystal structure and the morphological and structural evolution from a microscopic point of view.
Article
Nanoscience & Nanotechnology
Xin Liu, Quanchao Zhang, Dou Zhao, Ruichen Bai, Yinjie Ruan, Binbin Zhang, Fangpei Li, Menghua Zhu, Wanqi Jie, Yadong Xu
Summary: This article presents a study on the preparation of high-quality and high-yield hybrid perovskite FAPbBr3 single crystals using a solution growth method. By optimizing the growth conditions and seed behaviors, the authors successfully obtained large-size, well-shaped, and high-yield FAPbBr3 single crystals.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Physics, Condensed Matter
Mylene Sauty, Natalia Alyabyeva, Cheyenne Lynsky, Yi Chao Chow, Shuji Nakamura, James S. Speck, Yves Lassailly, Alistair C. H. Rowe, Claude Weisbuch, Jacques Peretti
Summary: In this study, scanning tunneling electroluminescence microscopy was used to investigate the unique radiative recombination properties near a defect in an InGaN/GaN quantum well. The results revealed intense emission peaks at higher energies close to the defect edges, which were not visible in the macrophotoluminescence spectrum. The quantitative information obtained from fitting the local tunneling electroluminescence spectra provided important insights into carrier localization in the quantum well.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2023)
Article
Engineering, Electrical & Electronic
R. M. Cadena, D. R. Ball, E. X. Zhang, S. Islam, A. Senarath, M. W. McCurdy, E. Farzana, J. S. Speck, N. Karom, A. O'Hara, B. R. Tuttle, S. T. Pantelides, A. F. Witulski, K. F. Galloway, M. L. Alles, R. A. Reed, D. M. Fleetwood, R. D. Schrimpf
Summary: Low-energy ion-induced breakdown and single event burnout (SEB) were observed in beta-gallium oxide (beta-Ga2O3) Schottky diodes at voltages lower than expected. Different responses were observed for alpha particles, Cf-252, and heavy-ion irradiation. TCAD simulations explained the breakdown as a result of ion strikes and defect-driven breakdown due to displacement-damage-induced defects in beta-Ga2O3. First-principles calculations showed the formation of less resistive defect clusters that can lead to destruction at reduced voltages.
IEEE TRANSACTIONS ON NUCLEAR SCIENCE
(2023)
Article
Physics, Applied
Feng Wu, Jacob Ewing, Cheyenne Lynsky, Michael Iza, Shuji Nakamura, Steven P. DenBaars, James S. Speck
Summary: In this article, the authors used advanced characterization techniques to study the active region compositions, V-defect formation, and V-defect structure in green and red LEDs. They identified two types of V-defects, one that promotes hole injection and one that is believed to be deleterious to high-efficiency LEDs.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Optics
Panpan Li, Hongjian Li, Yifan Yao, Kai Shek Qwah, Mike Iza, James S. Speck, Shuji Nakamura, Steven P. Denbaars
Summary: In this work, we demonstrate the vertical integration of nitride-based blue/green micro-light-emitting diode (mu LED) stacks with independent junction control using a hybrid tunnel junction (TJ). The hybrid TJ was grown by metal-organic chemical vapor deposition (p + GaN) and molecular-beam epitaxy (n + GaN). Different junction diodes were able to generate uniform blue, green, and blue/green emissions. The peak external quantum efficiency (EQE) of the TJ blue mu LEDs and green mu LEDs with indium tin oxide contact were 30% and 12%, respectively. Carrier transportation between different junction diodes was discussed. This work suggests a promising approach for vertical mu LED integration to enhance the output power of single LED chips and monolithic mu LEDs with different emission colors and independent junction control.
Article
Engineering, Electrical & Electronic
M. Ikram Md Taib, M. A. Ahmad, E. A. Alias, A. Alhassan, I. A. Ajia, M. M. Muhammed, I. S. Roqan, S. P. DenBaars, J. S. Speck, S. Nakamura, N. Zainal
Summary: In-surfactant was introduced during the growth of high temperature GaN quantum barriers and GaN interlayer in InGaN/GaN green LEDs. Results showed that the introduction of In-surfactant improved LED growth, particularly in the GaN interlayer. It improved the morphology of the interlayer, allowed it to serve as a good surface growth, and effectively improved the multi-quantum wells. Moreover, the introduction of In-surfactant shifted the emission wavelength towards red, reduced the forward voltage of the LEDs, and allowed faster carrier decay lifetime.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2023)
Article
Nanoscience & Nanotechnology
Matthew S. Wong, Aditya Raj, Hsun-Ming Chang, Vincent Rienzi, Feng Wu, Jacob J. Ewing, Emily S. Trageser, Stephen Gee, Nathan C. Palmquist, Philip Chan, Ji Hun Kang, James S. Speck, Umesh K. Mishra, Shuji Nakamura, Steven P. DenBaars
Summary: The electrical performance of III-nitride blue micro-light-emitting diodes (mu LEDs) with different tunnel junction (TJ) architectures grown by metalorganic chemical vapor deposition is investigated. The introduction of AlGaN layer above the n-side of the TJ layer improves the current density-voltage characteristic and the effects of AlGaN/GaN superlattices are examined. The band diagram simulation shows that a net positive polarization charge is formed at the AlGaN/GaN interface, leading to a reduction in tunneling distance and an increase in tunneling probability. Additionally, the proposed AlGaN-enhanced TJ design significantly enhances the wall-plug efficiency of mu LEDs.
Article
Physics, Applied
Fikadu Alema, Takeki Itoh, William Brand, Andrei Osinsky, James S. Speck
Summary: We investigated the controllable nitrogen doping of beta-Ga2O3 using ammonia diluted in nitrogen as a source of active nitrogen. The study looked at the effects of flow rate and substrate temperature on the doping efficiency and reproducibility. By increasing the flow rate of NH3/N-2, the nitrogen impurities incorporated into beta-Ga2O3 increased linearly. The presence of hydrogen in the film accompanied the nitrogen doping at low substrate temperatures.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Y. C. Chow, C. Lynsky, S. Nakamura, S. P. DenBaars, C. Weisbuch, J. S. Speck
Summary: Efficiency droop at high current densities is a common problem for InGaN-based LEDs, especially for conventional c-plane devices. This study introduces a method to reduce the internal electric fields in c-plane quantum wells by using doped barriers, which allows for a thick active region design and leads to improved LED performance.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Optics
J. Mickevic, E. Valkiunaite, Z. Podlipskas, K. Nomeika, S. Nargelas, G. Tamulaitis, Y. C. Chow, S. Nakamura, J. S. Speck, C. Weisbuch, R. Aleksieju
Summary: The dynamics of two distinct bands in non-polar m-plane InGaN/GaN multiple quantum wells (MQWs) were investigated using PL, CL, and DT spectroscopy. The shift in peak emission wavelength with increasing excitation was caused by competition between these bands. DT measurements attributed the high-energy PL band to optical transitions between ground QW states, while the low-energy PL band was associated with recombination of localized carriers. CL measurements confirmed the dispersion of deep localized states and suggested small-scale disorder. PL measurements showed that localized states are highly sensitive to indium content and structural parameters. Temperature-dependent PL studies revealed strong carrier-phonon interaction.
JOURNAL OF LUMINESCENCE
(2023)
Article
Nanoscience & Nanotechnology
Panpan Li, Hongjian Li, Yifan Yao, Norleakvisoth Lim, Matthew Wong, Mike Iza, Michael J. Gordon, James S. Speck, Shuji Nakamura, Steven P. DenBaars
Summary: We have shown a significant improvement in the quantum efficiency of InGaN red micro-light-emitting diodes (mu LEDs). The peak external quantum efficiency (EQE) of the packaged 80 x 80 mu m(2) InGaN red mu LEDs increased to 6.0% at 12A/cm(2), indicating a significant advancement in the efficiency exploration of InGaN red mu LEDs. The enhancement in EQE is attributed to improved quantum efficiency, confirmed by electron-hole wavefunction overlap and photoluminescence intensity ratio analysis. Additionally, ultrasmall 5x 5 mu m(2) InGaN red mu LEDs were obtained with a high peak EQE of 4.5%.
Article
Nanoscience & Nanotechnology
Takeki Itoh, Akhil Mauze, Yuewei Zhang, James S. Speck
Summary: Continuous Si doping in beta-Ga2O3 epitaxial films was achieved using plasma-assisted molecular beam epitaxy with a valved effusion cell for the Si source. Secondary ion mass spectroscopy results indicated flat and sharply turned Si doping profiles in beta-Ga2O3. The Si doping concentration could be controlled by adjusting the cell temperature or the valve aperture of the Si effusion cell. High crystal quality and smooth surface morphologies were observed in Si-doped beta-Ga2O3 films grown on (010) and (001) substrates. The Si-doped (001) beta-Ga2O3 epitaxial film exhibited an electron mobility of 67 cm(2)/Vs at a Hall concentration of 3 x 10(18) cm(-3).
Article
Psychology, Developmental
Erin P. Vaughan, Julianne S. Speck, Paul J. Frick, Toni M. Walker, Emily L. Robertson, James V. Ray, Tina D. Wall Myers, Laura C. Thornton, Laurence Steinberg, Elizabeth Cauffman
Summary: Research on proactive and reactive aggression in adolescents and young adults found that these two types of aggression have unique developmental trajectories and distinct covariates. Proactive aggression was influenced by callous-unemotional traits, while reactive aggression was predicted by impulsivity. These findings highlight the importance of considering the specific factors associated with each type of aggression in understanding and addressing aggressive behaviors.
DEVELOPMENT AND PSYCHOPATHOLOGY
(2023)
Article
Physics, Applied
Wan Ying Ho, Cameron W. Johnson, Tanay Tak, Mylene Sauty, Yi Chao Chow, Shuji Nakamura, Andreas Schmid, Jacques Peretti, Claude Weisbuch, James S. Speck
Summary: In this study, the lateral distribution of the junction current in an electrical biased p-n GaN diode was measured using electron emission microscopy with a low-energy electron microscope. The vacuum level on the diode surface was reduced by cesium deposition to achieve negative electron affinity, allowing emitted overflow electrons on the biased diode surface to be imaged for their spatial distribution. The obtained results were compared with Joyce and Wemple's analytical solutions [J. Appl. Phys. 41, 3818 (1970)] and showed a good match.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Wan Ying Ho, Abdullah I. Alhassan, Cheyenne Lynsky, Yi Chao Chow, Daniel J. Myers, Steven P. DenBaars, Shuji Nakamura, Jacques Peretti, Claude Weisbuch, James S. Speck
Summary: Using electron emission spectroscopy, researchers measured and analyzed the energy distribution of vacuum emitted electrons from electrically driven InGaN/GaN green light emitting diodes (LEDs) with and without a prewell superlattice (SL). They discovered a high-energy upper valley peak at approximately 1.7 eV above the I' valley in samples without a prewell SL, which is attributed to trap-assisted Auger recombination (TAAR). The absence of this peak in the sample with a prewell SL suggests the gettering of unidentified impurities that act as TAAR centers.
Article
Physics, Applied
Saulius Marcinkevicius, Jacob Ewing, Rinat Yapparov, Feng Wu, Shuji Nakamura, James S. Speck
Summary: Hole injection through V-defect sidewalls into all quantum wells can increase the efficiency of long wavelength GaN light emitting diodes, allowing for population of all wells in a multiple QW structure.
APPLIED PHYSICS LETTERS
(2023)
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)
