Article
Engineering, Electrical & Electronic
Reetendra Singh, Anand Roy, C. N. R. Rao
Summary: Carbon-doped gallium nitride is a promising material for optoelectronic devices, and studying its defects can provide insights into possible transitions. Carbon-doped GaN was obtained through a simple solid-gas reaction. Spectroscopic analysis revealed the presence of an isolated C-N defect state and the formation of a C-N-O-N complex. In heavily doped samples, blue luminescence related to oxygen defects was quenched, and carbon-related yellow luminescence appeared.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Jinyuan Xu, Ailing Chen, Linfeng Yu, Donghai Wei, Qikun Tian, Huimin Wang, Zhenzhen Qin, Guangzhao Qin
Summary: In this paper, the stable structure of a monolayer CuI with ultra-low thermal conductivity and an ultra-wide direct bandgap is predicted from first-principles calculations. This material shows potential applications in transparent and wearable electronics.
Article
Optics
Ekaterina Dementeva, Kseniia N. Orekhova, Marina G. Mynbaeva, Maria Zamoryanskaya
Summary: This paper investigates the cathodoluminescent properties of point defects in bulk GaN samples grown by HVPE technique. The cathodoluminescence spectra of GaN show two broad luminescence bands in the blue and yellow ranges. Each luminescence band is associated with several point defects - luminescence centers with similar spectral positions but different decay times. The paper proposes a technique for estimating the relative content of luminescent centers based on measuring cathodoluminescence intensity dependence on electron beam current density and decay times. Changes in the relative contents of point defects - luminescence centers are determined for different regions of the sample, and the excitation capture efficiency is constant for luminescence centers emitting in the yellow range.
JOURNAL OF LUMINESCENCE
(2022)
Article
Engineering, Electrical & Electronic
Saurabh Kharwar, Sangeeta Singh, Neeraj K. Jaiswal
Summary: The study investigates the interaction between gallium nitride nanoribbon (GaNNR) and toxic heavy metals (HMs). Comparisons are made between the structural and electronic behavior of HM-interacted GaNNRs and bare GaNNRs, revealing significant changes. Lead (Pb)-ZGaNNR-Pb is found to be the most stable structure, followed by zinc (Zn)-ZGaNNR-Zn and mercury (Hg)-ZGaNNR-Hg. The conductivity of HM-interacted GaNNRs suggests their potential applications as nanoscaled sensors for toxic HM detection.
IEEE SENSORS JOURNAL
(2023)
Article
Physics, Multidisciplinary
Zheng-Zhao Lin, Ling Lu, Xue-Feng Zheng, Yan-Rong Cao, Pei-Pei Hu, Xin Fang, Xiao-Hua Ma
Summary: AlGaN/GaN high electron mobility transistors (HEMTs) exhibit significant changes in electrical characteristics after heavy ion irradiation, including threshold voltage shift and decrease in saturation currents. Irradiation induces defects and tunneling sites, increasing current collapse and the number of surface state traps.
Article
Engineering, Electrical & Electronic
Daniel M. Fleetwood, Andrew O'Hara, Theresa Stellwag Mayer, Michael R. Melloch, Sokrates T. Pantelides
Summary: The significant increase in thermal carrier generation rates in MBE-grown p-i-n-i-p GaAs structures is attributed to deactivation of hydrogen-defect/impurity complexes during high-intensity, low-energy electron-beam irradiation. Quantum calculations suggest that deactivation of oxygen impurities is likely the cause of this degradation, with electric-field and excess-carrier-induced dehydrogenation of O-As-H complexes identified as a likely rate-limiting process.
IEEE TRANSACTIONS ON NUCLEAR SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Junting Chen, Junlei Zhao, Sirui Feng, Li Zhang, Yan Cheng, Hang Liao, Zheyang Zheng, Xiaolong Chen, Zhen Gao, Kevin J. J. Chen, Mengyuan Hua
Summary: In this study, the GaN surface is converted into a GaON epitaxial nanolayer through a two-step oxidation-reconfiguration process, overcoming the vulnerability of the GaN surface and enhancing the stability and reliability of GaN-based devices. The GaON nanolayer derived from GaN possesses advantages such as a wide bandgap, high thermodynamic stability, and large valence band offset with a GaN substrate, which can be further utilized to improve the performance of GaN-based devices in various applications.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Physical
Malgorzata Sznajder, Roman Hrytsak
Summary: Integration of diamond with GaN-based high-electron-mobility transistors improves thermal management, influencing the reliability, performance, and lifetime of GaN-based devices. By conducting first principles calculations on the stability of diamond-GaN interfaces, researchers have identified stable adsorption sites for C atoms on Ga- and N-terminated surfaces, and demonstrated ways to improve the energetic stability of diamond-GaN interfaces through reconstructions induced by substitutional dopants.
Article
Materials Science, Multidisciplinary
D. S. Gomes, J. M. Pontes, S. Azevedo
Summary: This study investigates the structural stability and electronic properties of hydrogenated gallium nitride monolayers (GaN(H)) using density functional theory (DFT), and explores the modulation of these properties through defects and chemical doping. The M1-GaN(H) structure exhibits better formation energy and stability, acts as a semiconductor with a wide bandgap of 3.45 eV, and shows potential for electronic device applications.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2022)
Article
Chemistry, Physical
Jerome A. Cuenca, Matthew D. Smith, Daniel E. Field, Fabien C-P Massabuau, Soumen Mandal, James Pomeroy, David J. Wallis, Rachel A. Oliver, Iain Thayne, Martin Kuball, Oliver A. Williams
Summary: The study investigates the thermal stresses induced by diamond directly deposited onto III-nitride (III-N) heterostructure membranes, using analytical methods, numerical models, and experimental validation. It is found that the thermal stresses are mainly caused by the mismatch in coefficient of thermal expansion (CTE), and can be reduced by pre-stressing the membrane.
Article
Engineering, Electrical & Electronic
S. Garcia-Sanchez, I. Iniguez-de-la-Torre, S. Perez, T. Gonzalez, J. Mateos
Summary: Monte Carlo simulations were used to optimize the epilayer structure of GaN planar Gunn diodes to achieve ultrahigh-frequency oscillations. Practical considerations were taken into account, such as limitations of the fabrication process and mitigation of self-heating effects. The best results were obtained with an active layer thickness of 150 nm and a doping of 5 x 10(18) cm(-3), providing 350 GHz Gunn oscillations with a contact separation of 0.5 μm.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Chemistry, Multidisciplinary
Yahya Mohtashami, Larry K. Heki, Matthew S. Wong, Jordan M. Smith, Jacob J. Ewing, William J. Mitchell, Shuji Nakamura, Steven P. DenBaars, Jon A. Schuller
Summary: Researchers demonstrate metasurface LEDs that emit directional or focused light, showing advanced phase control technology. These metasurface LEDs exhibit better external quantum efficiency than unpatterned LEDs, providing possibilities for the development of high-efficiency metal-free LED devices.
Article
Engineering, Electrical & Electronic
Sulagna Chatterjee, Moumita Mukherjee
Summary: This article reports the opto-electronic switching properties of a GaN/AlGaN lateral Avalanche Transit Time (ATT) diode oscillator. A novel technique is used to incorporate the 2DEG effect in the two-terminal device through the conduction band offset and application of Cathode Field Plate (CFP) combined with lateral orientation. The performance superiority of the proposed electrical and optical switches over conventional silicon devices is demonstrated. The newly designed ATT diode shows enhanced performance due to the high mobility 2DEG transport region formed by the GaN/AlGaN conduction band offset and the unique CFP and lateral orientation.
MICROSYSTEM TECHNOLOGIES-MICRO-AND NANOSYSTEMS-INFORMATION STORAGE AND PROCESSING SYSTEMS
(2023)
Article
Engineering, Electrical & Electronic
Muhammad Saddique Akbar Khan, Hui Liao, Guo Yu, Imran Iqbal, Menglai Lei, Rui Lang, Zehan Mi, Huanqing Chen, Hua Zong, Xiaodong Hu
Summary: Two innovative techniques, serpentine channel pattern sapphire substrate (SCPSS) and InGaN interlayer (IL), are proposed to effectively reduce threading dislocations (TDs) in GaN-based devices. Experimental results demonstrate the effectiveness of these techniques in decreasing the number of TDs and improving material quality.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2021)
Article
Engineering, Electrical & Electronic
Giovanni Alfieri, Yusuke Fujii, Ruggero Micheletto
Summary: Opto-electronic properties of semiconductors can be altered by impurities and their complexes with intrinsic point defects, such as vacancies. Helium is one such impurity that is incorporated into gallium nitride (GaN) for various technological purposes. However, its electrical activity in GaN and its impact on dopants are not known. In this study, a density functional theory was used to investigate the behavior of substitutional helium and its complexes in wurtzite GaN. It was found that helium is unstable at nitrogen sites and forms nitrogen vacancies, leading to the creation of donor states close to the valence band edge. On the other hand, the presence of a gallium vacancy leads to the formation of an energetically stable complex that generates acceptor states close to the conduction band edge. These findings provide insights into the behavior of helium in GaN and its potential implications for device isolation.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Muhammad Haris Azhar, Tayyaba Noor, Naseem Iqbal, Neelam Zaman, Sarah Farrukh
Summary: This study uses a novel adsorbent Metal Organic Framework (MOF) and its composites to adsorb CO2. Experiment results show that 5 wt% g-C3N4/Ni-BDC MOF exhibits the highest adsorption capacity.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
Ayumu Nodera, Shinya Aikawa
Summary: In this study, a CO2 sensor capable of low-temperature operation was fabricated using an open-channel-type thin-film transistor structure with a polar surface of an oxide semiconductor. The sensor showed a sensitivity 2.9 times greater than that under an inert N2 atmosphere at an operating temperature of only 150 degrees C. The results suggest that TFTs fabricated with polar surfaces of oxide semiconductors are useful for gas-sensing applications.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
Bindhyabasinee Mishra, Jyotirmayee Nanda, Subhra S. Brahma, K. J. Sankaran, R. Sakthivel, S. Ghadei, S. Suman
Summary: In this study, a series of polycrystalline mixed spinel ferrites were synthesized and characterized. The Mg0.5Zn0.5La0.05Fe1.95O4 ferrite showed the best response and recovery time, indicating its potential as a material for LPG sensing.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2024)
Review
Materials Science, Multidisciplinary
Rajashree Panda, Mitrabhanu Behera, A. Arun Kumar, Dhananjay Joshi
Summary: Rare earth doped aluminate-based phosphors are preferred over sulfide-based phosphors. The unique luminescence features of lanthanide-based materials are being utilized for multidisciplinary research and inventive applications. The past years have seen an increase in research interest in aluminate-based phosphors, leading to improvements in their long-lasting phosphorescence and phosphorescence efficiencies. Combustion synthesis route is an efficient technique for preparing nano-phosphor due to its simplicity and cost-effectiveness.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2024)
Review
Materials Science, Multidisciplinary
Younes Zohrabi
Summary: Water is essential for the survival of living organisms, but industrialization has led to contamination of water sources with heavy metals and harmful pollutants. Magnetic nano ferrites have shown potential in effectively removing heavy metals from water due to their magnetic characteristics, high surface area, surface active sites, chemical stability, and ease of modification. This review explores recent literature on the synthesis and application of magnetic ferrites for removing heavy metals from water, aiming to provide a comprehensive understanding for future research.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
Baolin Liu, Chenxin Xie, Guanglei Qian, Lishan Zhou, Chenglei Zhang, Lingzhi Zhu
Summary: In this study, a self-cleaning CuO-PdO-Pd/Ti membrane has been developed for the removal of small-sized pollutants. The membrane exhibited superior removal ability and permeability compared to conventional membranes, and maintained high efficiency even after repeated tests. The CuO-PdO-Pd/Ti membrane also showed excellent removal efficiency when treating real wastewater, indicating its high potential for practical applications.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
Debabrata Panda, Akhilesh Kumar Sahu, Krunal M. Gangawane
Summary: A variety of hierarchical nanoporous silica aerogels were synthesized from well-dispersed silica sols, exhibiting diversified particle distributions and excellent thermal properties. The silica aerogels showed low thermal conductivity and high-temperature resilience. Surface modification and dilution of silica sols further improved the thermal resistance of the aerogels. The resilient skeleton structure developed from tiny particles effectively restricted heat dissipation and maintained the porous network at high temperatures.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
Hardy Shuwanto, Hairus Abdullah, Young Ku, Jenni Lie
Summary: In this study, a defective system of V-doped Fe2O3 with Pt as a cocatalyst was used for photoelectrochemical water oxidation. The defects in the VFPt-2.5 photoanode were characterized by XPS and EPR analyses. The SEM and TEM analyses revealed that the electrodeposited V-doped alpha-Fe2O3 had a nanosized morphology with an average diameter of 12 nm and a thickness of 300 nm. Under light irradiation, the VFPt-2.5 photoanode achieved a remarkable onset potential and photocurrent density. The stability test showed that Pt helped overcome the charge recombination caused by surface states.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
Reza Gholipur, Hemin Mohammed Ali Khalifa, Khatereh Afrouzeh
Summary: Developing doped cathode materials is crucial for achieving low cost and high-performance energy storage. LiMn1.977(Ce, Cu, Ti, CeCuTi)0.023O4 nanoparticles show unmatched high structural stability, capacity, and safety during charge/discharge cycles. Ti-doped LiMn2O4 cathode calcined at 700 degrees C demonstrates the highest capacity and retention when multi-walled carbon nanotubes are added. The presence of titanium increases the porosity for reversible lithium storage and the dielectric constant.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
T. Amutha, M. Rameshbabu, S. Sasi Florence, G. Ramalingam, S. Muthupandi, K. Prabha
Summary: This research provides an overview of the structural analysis and magnetic characteristics of dilute magnetic semiconductor oxides (DMSOs) based on binary metal oxide nanomaterials with different ferromagnetic or paramagnetic dopants. The coprecipitation method was used to create nanoparticle samples, and the results showed certain ferromagnetic behavior and increased magnetic properties.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
Preeti Kumari, Vipul Srivastava, Ramesh Sharma, Hamid Ullah
Summary: In this study, the rare-earth ferrites perovskite RFeO3 (R = Pr, Nd) were investigated for their various properties including structural, electronic, magnetic, optical, thermodynamic, and thermoelectric behavior. The study found that these materials exhibit half-metallic behavior under certain conditions, and their optical and thermoelectric properties were evaluated, making them potential candidates for spintronic devices and UV absorbers.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
Shuting Yuan, Tianchi Wang, Tian Feng, Jian Kong
Summary: In this study, Fe/Fe3O4/C hollow electromagnetic wave absorbers were prepared using hollow ceiba fibers as templates. The proposed hollow structure could reflect and scatter electromagnetic waves multiple times, leading to significant energy consumption. The impedance matching of magnetic materials and biochar enabled the joint absorption of magnetic and dielectric losses to absorb electromagnetic waves.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
G. R. Mamatha, B. R. Radha Krushna, J. Malleshappa, S. C. Sharma, Satish Kumar, C. Krithika, Nandini Robin Nadar, Dileep Francis, K. Manjunatha, Sheng Yun Wu, H. Nagabhushana
Summary: Nanostructured SrAl2O4:Tb3+/M (M = Li+, Na+, K+, Ca2+, Bi3+) green nanophosphors were synthesized using an environmentally friendly combustion process and Areca nut as a sustainable fuel source. The introduction of alkali metal co-dopants optimized the luminescent intensity and showed potential for data security applications.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
Tomoyuki Tachibana, Akihiro Yabuki
Summary: A one-step thermal-reduction method was used to synthesize copper sulfide films with different compositions and pillar-like structures, through adjusting the sulfur ratio and incorporating excess sulfur during the synthesis process.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
Manal A. Mahdy, I. K. El Zawawi, Manal Mounir Ahmad
Summary: Pure PVA and its nanocomposites with CuO and/or CoFe2O4 films were prepared and characterized. The optical properties of the films can be modulated by controlling the percentage of CuO and/or CoFe2O4. The nanocomposites exhibit good ferromagnetic behavior, making the prepared films potentially useful in antenna system miniaturization and flexible magneto-electronic applications.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2024)