Article
Nuclear Science & Technology
Junesic Park, Byung-Gun Park, Gwang-Min Sun
Summary: The effect of thermal annealing on defect recovery of neutron-irradiated 4H-SiC was investigated. Electrical characteristics of epitaxial layers were analyzed under different neutron fluences and annealing times. The results showed high carrier compensation in the neutron-irradiated samples, which could be recovered up to 77% with annealing. Intrinsic defects of 4H-SiC and a previously unknown defect were identified, and their concentrations decreased with annealing.
NUCLEAR ENGINEERING AND TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
R. L. Gao, X. Du, W. Y. Ma, B. Sun, J. L. Ruan, X. Ouyang, H. Li, L. Chen, L. Y. Liu, X. P. Ouyang
Summary: This study investigates the characteristics of 4H-SiC PIN diode detectors under harsh neutron irradiation environments. The results show that the detectors exhibit excellent neutron radiation tolerance and maintain relatively stable performance even after irradiation.
SENSORS AND ACTUATORS A-PHYSICAL
(2022)
Article
Nanoscience & Nanotechnology
Mingtao Hu, Ping Wang, Ding Wang, Yuanpeng Wu, Shubham Mondal, Danhao Wang, Elaheh Ahmadi, Tao Ma, Zetian Mi
Summary: In this study, we investigated the molecular beam epitaxy and characterization of N-polar AlN on C-face 4H-SiC substrates. The results showed that the N-polar AlN films grown under optimized conditions have a smooth surface and strong excitonic emission in the deep UV. Additionally, most dislocations in the AlN grown on SiC substrate were terminated/annihilated.
Article
Engineering, Electrical & Electronic
Hao Luo, Jiajun Li, Guang Yang, Ruzhong Zhu, Yiqiang Zhang, Rong Wang, Deren Yang, Xiaodong Pi
Summary: This study investigates the threading dislocations in 4H-SiC and their surface characteristics, such as the diameters, depths, and inclination angles of etched pits. Different types of dislocations can be distinguished based on these surface features. The presence of dislocations affects the electronic and optical properties of n-type 4H-SiC. The findings of this study provide insights for optimizing n-type 4H-SiC by manipulating the properties of dislocations.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
Article
Engineering, Electrical & Electronic
Clement Berger, Daniel Alquier, Micka Bah, Jean-Francois Michaud
Summary: This study focuses on obtaining good ohmic contact using laser annealing on a deposited titanium layer. The results show that with proper laser annealing conditions, contacts with good conductivity can be achieved, and the performance is better than previous studies using titanium laser annealing.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Haixu Liu, Mengmeng Jin, Jiejing Li, Zhipeng Li, Dunwen Zuo
Summary: The irradiation threshold of 4H-SiC under picosecond laser action was calculated, and the influence of laser parameters on the size of 4H-SiC was studied. The effect of laser parameters on the mechanical properties of 4H-SiC was also investigated. The results show that laser energy density has a significant modification effect on the mechanical properties of 4H-SiC.
Article
Chemistry, Multidisciplinary
Sheng'ou Lu, Hongyu Chen, Wei Hang, Rong Wang, Julong Yuan, Xiaodong Pi, Deren Yang, Xuefeng Han
Summary: The effect of nitrogen doping on dislocation proliferation in SiC crystals was investigated. The thermal field and thermal stress during PVT growth were calculated, and the dislocation density was calculated based on the Alexander-Haasen model. By comparing the calculation and experimental results, a possible value of effective stress was proposed to evaluate the effect of nitrogen doping on dislocation density in n-type SiC.
Article
Chemistry, Physical
A. M. Adam, A. El-Khouly, A. K. Diab
Summary: This study demonstrates that replacing Bi atoms with Ag atoms in the n-type Bi2-xAgxSe3 system can result in higher electrical conductivity and larger Seebeck coefficient. The concerned alloys were prepared by high temperature melting, with microstructure and surface morphology identified through XRD and SEM-EDX analysis. Promising ZT values were achieved due to the high electrical conductivity and Seebeck coefficient of some doped alloys.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Engineering, Electrical & Electronic
Baohua Tian, Haiping Shang, Dahai Wang, Yang Liu, Weibing Wang
Summary: This paper proposes an in situ extraction method to determine the piezoresistive coefficients of n-type 4H-SiC and fabricates two piezoresistive pressure sensors based on SiC sealed cavity structure for characterization. By fitting the experimental data and numerical calculation results, the longitudinal and transverse piezoresistive coefficients are obtained and the reliability of the extraction method is verified. This research is of significant value for understanding the piezoresistive effect in materials and guiding the design and performance optimization of SiC-based sensors.
IEEE SENSORS JOURNAL
(2022)
Article
Chemistry, Physical
Tihomir Knezevic, Eva Jelavic, Yuichi Yamazaki, Takeshi Ohshima, Takahiro Makino, Ivana Capan
Summary: In this study, boron-related defects in low-doped n-type 4H-SiC semitransparent Schottky barrier diodes (SBDs) were investigated using minority carrier transient spectroscopy (MCTS). Boron, introduced during chemical vapor deposition (CVD) crystal growth, led to the presence of shallow (B) and deep boron (D-center) defects, with concentrations as high as 1 x 10(15) cm(-3). Despite the higher concentration of boron compared to nitrogen doping, the steady-state electrical characteristics of the n-type 4H-SiC SBDs remained unaffected.
Article
Engineering, Electrical & Electronic
Zhao-Yang Yang, Ying Wang, Xing-ji Li, Jian-qun Yang, Ding-kun Shi, Fei Cao
Summary: A Schottky diode using Mo-C alloy as the Schottky metal was proposed in this study, showing near-ideal behavior at high annealing temperatures. The electrical properties of the structure were analyzed at different annealing temperatures, and it was found to have good stability at high temperatures.
MICROELECTRONIC ENGINEERING
(2021)
Article
Materials Science, Ceramics
Haiyan Shi, Qi Song, Yu Hou, Song Yue, Yan Li, Zhe Zhang, Man Li, Kunpeng Zhang, Zichen Zhang
Summary: This study presents a comprehensive investigation of the structural transformation and residual stress induced by femtosecond laser irradiation on a 4H-SiC target. The obtained results show energy-dependent structural characteristics and spatial distribution. It provides insights into the laser-material interaction mechanisms and offers suggestions for improving surface quality.
CERAMICS INTERNATIONAL
(2022)
Article
Physics, Applied
M. Vivona, G. Greco, G. Bellocchi, L. Zumbo, S. Di Franco, M. Saggio, S. Rascuna, F. Roccaforte
Summary: This paper investigated the electrical behavior of WC Schottky barrier on 4H-SiC, revealing temperature-dependent changes in barrier height and ideality factor, indicating lateral inhomogeneity. By considering this inhomogeneity, the temperature-dependent leakage current under reverse bias could be better described.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Ezekiel Omotoso, Walter E. Meyer, Emmanuel Igumbor, Thulani T. Hlatshwayo, Aletta R. E. Prinsloo, F. Danie Auret, Charles J. Sheppard
Summary: In this study, nitrogen-doped 4H-SiC samples were bombarded with 167 MeV xenon ions and then annealed before the fabrication of Schottky barrier diodes. The implanted devices showed generation-recombination processes and induced two new deep level defects with similar characteristics to defects induced by MeV electron irradiation.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2022)
Article
Chemistry, Multidisciplinary
Chih Shan Tan
Summary: This research investigates the potential advantages of 4H-SiC as a material for next-generation semiconductor devices and proposes that defect-selective technology could be used to develop large-scale 4H-SiC substrates with improved electrical conductivity, thereby contributing to a reliable fabrication process for future semiconductor applications.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Chemistry, Physical
V. S. Ganesha Krishna, M. G. Mahesha
Summary: This study investigates the anharmonic properties of the longitudinal optical phonon mode in Mg-doped ZnS thin films using temperature-dependent Raman spectra. The results indicate low anharmonicity and fast decay of the phonon mode. Additionally, the film surface exhibits chemical homogeneity, and Raman analysis provides insights into the phonon-phonon interaction mechanism.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Engineering, Electrical & Electronic
Swati M. Pujar, Sahana Moger, Gowrish K. K. Rao, M. G. Mahesha, Ashwath Kulal
Summary: Cost effective SILAR method was used to deposit ZnO thin films on glass substrates for thin film UV photodetector applications. The film properties such as structure, morphology, optical and electrical properties were investigated in detail with respect to the cationic precursor molarity. The increase in solution molarity resulted in an increased crystallite size and nearly stoichiometric composition of the films. SEM images showed the presence of rod or needle-like structures in the films. The films exhibited modified optical energy band gap and reduced defect states at higher molarities, leading to enhanced UV emission.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2023)
Article
Materials Science, Multidisciplinary
Chiranjit Nandi, Rohan Phatak, Swayam Kesari, Muhammed Shafeeq, Geeta Patkare, S. N. Jha, Rekha Rao, Sudhir Mishra, Amrit Prakash, P. G. Behere
Summary: This study investigates the solid solubility of uranium in Nd2Zr2O7 pyrochlore and its phase evolution for nuclear waste immobilization and inert matrix fuel applications. Nd2Zr2-xUxO7 samples were synthesized and characterized, revealing that uranium forms a solid solution and the phase evolves from pyrochlore structure to fluorite-type structure under different conditions. Raman spectroscopy was used to examine the local structures, and chemical analysis showed different O/U ratios for the reduced and oxidized samples.
JOURNAL OF NUCLEAR MATERIALS
(2023)
Article
Spectroscopy
V. S. Ganesha Krishna, M. G. Mahesha
Summary: This report discusses the temperature-induced variation in the phonon properties and the spatial variation in the Raman spectra for spray-deposited Zn0.98Mn0.02S thin films. The novelty of this work lies in the study of the temperature dependence of the Raman line position, line width, and phonon lifetime using theoretical models that consider thermal expansion and three- and four-phonon anharmonic effects. The lifetime of the LO phonon in the Zn0.98Mn0.02S thin film was as low as 0.234 ps, indicating its suitability for optical limiting applications. The intensity ratio I-2LO/I-1LO ranges around 0.5 in most (x, y) positions in the Raman mapping data, suggesting the nanocrystalline nature of Zn0.98Mn0.02S.
JOURNAL OF RAMAN SPECTROSCOPY
(2023)
Article
Materials Science, Multidisciplinary
M. Anitha, K. Sandeep Rao, Rajak Syed, S. Kesari, R. Rao, D. K. Singh, S. N. Achary, Vivekanand Kain
Summary: This manuscript presents the temperature evolution of crystal structure and vibrational properties of tetragonal GdVO4. The material exhibits anisotropic expansion with a larger coefficient of thermal expansion along the c-axis. The thermal expansion behavior is mainly influenced by the orientation and expansion of Gd-O bonds in the structure. The Raman spectroscopic investigations reveal a decreasing trend in all observed phonon mode frequencies and the low energy modes contribute significantly to the expansion of GdVO4.
MATERIALS CHEMISTRY AND PHYSICS
(2023)
Article
Chemistry, Physical
Ashwini Udupi, Pramoda Kumara Shetty, Priyada Panikkath, Pradip Kumar Sarkar
Summary: This study investigates the estimation of neutron ambient dose equivalent and effective dose using prompt gamma intensities. Different materials were used as outer layer covering for detection systems, and iron, nickel, zinc, and copper showed promising results as replacements for boron in high energy neutron distributions.
RADIATION PHYSICS AND CHEMISTRY
(2023)
Article
Engineering, Electrical & Electronic
Sahana Nagappa Moger, M. G. Mahesha
Summary: The present research focuses on the properties of p-Si/ ZnSxSe1-x heterojunctions in photodetector applications. The heterostructures were fabricated by depositing ZnSSe on Si wafer using thermal co-evaporation technique. GIXRD study showed that the films were in cubic phase and the prominent peak shifted with composition x. Photoluminescence confirmed the presence of point defects and emission related to higher Zn content in the films. Temperature-dependent Raman analysis revealed the shift of longitudinal optical phonon modes with decreasing temperature, which described the variation of lattice parameters. The photoresponse of p-Si/ ZnSxSe1-x heterostructures was investigated and found that the sample with x = 0.8 exhibited high photosensitivity and is suitable for photodetector applications.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2023)
Article
Materials Science, Multidisciplinary
Chiranjit Nandi, Rohan Phatak, Muhammed Shafeeq, Swayam Kesari, Rekha Rao, Amrit Prakash
Summary: The Am-substituted UO2 solid solutions are considered as advanced fuels for heterogeneous transmutation of americium, while the U-substituted Am2O3 with cubic structure is considered as a promising candidate for radioisotope heat unit and radioisotope thermoelectric generator.
JOURNAL OF NUCLEAR MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
C. Aparna, Pramoda Kumara Shetty, M. G. Mahesha, I. Yashodhara, N. Karunakara
Summary: This article investigates the changes in the structure, optics, and electrical properties of indium oxide thin film after gamma irradiation. The sensitivity for gamma sensing applications is also estimated. The thin film was deposited on a glass substrate using spray pyrolysis and irradiated with different doses of gamma radiation. The optical properties, including transmittance and bandgap energy, were analyzed. Additionally, photoluminescence and resistivity measurements were taken. The sensitivity of the film was found to be between 10.7 and 53.4 mA/cm(2)/Gy.
JOURNAL OF MATERIALS SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Chiranjit Nandi, V. Grover, Swayam Kesari, A. K. Poswal, Rohan Phatak, S. N. Jha, Rekha Rao, Amrit Prakash, P. G. Behere
Summary: The formation mechanism and defect dynamics in U1-xCexO2 +/-delta solid solutions were studied using X-ray diffraction (XRD) analysis, Raman spectroscopy, and X-ray absorption near-edge structure (XANES) spectroscopy. XRD studies showed the formation of single-phase solid solutions with a fluorite-type structure at x <= 0.2 and a single-phase fluorite-type structure with broadened diffraction peaks at 0.3 <= x <= 0.8 under reducing conditions. Under oxidizing conditions, single-phase solid solutions with a fluorite-type structure were formed at x >= 0.4. The presence of Ce3+ in solid solutions was confirmed through XANES studies, despite synthesis under oxidizing conditions.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(2023)
Article
Materials Science, Multidisciplinary
C. Aparna, Pramoda Kumara Shetty, M. G. Mahesha
Summary: Zinc-doped indium oxide thin film was deposited on a glass substrate using the spray pyrolysis method. The film exhibited a polycrystalline cubic structure, with a shift in preferred growth orientation on higher doping levels. Surface morphology had a significant influence on the film's physical properties and optical transmittance decreased with doping. The presence of defects and the influence of Zn doping on the electrical properties were also confirmed.
MATERIALS CHEMISTRY AND PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Maithili K. Rao, M. Selvakumar, M. G. Mahesha, Selvaraj Paramasivam, K. Reshma Dileep, Nimitha S. Prabhu, Ganapathy Veerappan, S. Senthilkumar, Sudha D. Kamath
Summary: By introducing 1D-pyrrolidinium lead iodide (PyPbI3) into 3D-Methylammonium lead iodide (MAPbI3) perovskite, the stability issues of perovskites have been improved and solar cells have been successfully fabricated.
MATERIALS CHEMISTRY AND PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Adithya Prakash, M. G. Mahesha
Summary: This article investigates the influence of isovalent dopant Zinc on the electronic, optical, and structural characteristics of copper oxide thin films. The results show that Zinc doping effectively modifies the electrical and structural properties of the films without sacrificing their excellent optical properties.
MATERIALS CHEMISTRY AND PHYSICS
(2023)
Article
Construction & Building Technology
J. Lokesh, A. N. Padmasali, M. G. Mahesha, S. G. Kini
Summary: The spectral power distribution (SPD) is influenced by electrical and thermal loading and plays a significant role in evaluating the performance of LED lighting. Statistical models are commonly used for SPD prediction, but become complex and time-consuming with more than two inputs. Artificial Neural Network (ANN) models offer a solution to this problem. This study aims to enhance the practicality of ANN in lighting applications, utilizing different neural network structures (models 1, 2, and 3) to forecast SPD under various electrical and thermal stress levels at zero hours. Model 1 is identified as the best SPD prediction model based on the absolute prediction error (APE) set at 5%, and its time-based SPD prediction for LED luminaires is validated using temperature, wavelength, and time as input parameters.
LIGHTING RESEARCH & TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
V. S. Ganesha Krishna, M. G. Mahesha
Summary: In this study, the impact of divalent dual dopants on ZnO was investigated by examining the structural and spectroscopic properties of (Mg,Mn)-doped ZnO thin films. The analysis of current-voltage characteristics of (Mg,Mn)-doped ZnO/p-Si heterojunctions showed potential for light-emitting applications. The addition of Mg dopant increased the band gap and optical disorder, while retaining good crystallinity and emission properties.
