Journal articles: 'Gallium industry'

1

Chen, Wei-Sheng, Li-Lin Hsu, and Li-Pang Wang. "Recycling the GaN Waste from LED Industry by Pressurized Leaching Method." Metals 8, no. 10 (October 22, 2018): 861. http://dx.doi.org/10.3390/met8100861.

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In recent years, with the increasing research and development of the light-emitting diode (LED) industry, which contains gallium nitride (GaN), it is expected that there will be a large amount of related wastes in the future. Gallium has an extremely high economic value, therefore, it is necessary to establish a recycling system for the GaN waste. However, GaN is a direct-gap semiconductor and with its high energy gap, high hardness, and high melting point, these make it difficult to recycle. Therefore, this study will analyze the physical characteristics of LED wastes containing GaN and carry out various leaching methods to leach the valuable metals from the waste optimally. Different acids are used to find out the best reagent for gallium leaching. Different experimental parameters are discussed, such as the effect of the different acid agents, concentration, pressure, liquid-solid mass ratio, temperature and time, which influence the leaching efficiency of gallium. Finally, acid leaching under high pressure is preferred to leach the GaN waste, and hydrochloric acid is used as the leaching solution because of its better leaching efficiency of gallium. Optimally, the leaching efficiency of gallium can reach 98%.

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Moskalyk, R. R. "Gallium: the backbone of the electronics industry." Minerals Engineering 16, no. 10 (October 2003): 921–29. http://dx.doi.org/10.1016/j.mineng.2003.08.003.

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CARVALHO, MARCELO S., KÁTIA CRISTINA M. NETO, ARMI W. NOBREGA, and JOÃO A. MEDEIROS. "Recovery of Gallium from Aluminum Industry Residues." Separation Science and Technology 35, no. 1 (January 2000): 57–67. http://dx.doi.org/10.1081/ss-100100143.

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Chen, Wei-Ting, Lung-Chang Tsai, Fang-Chang Tsai, and Chi-Min Shu. "Recovery of Gallium and Arsenic from Gallium Arsenide Waste in the Electronics Industry." CLEAN - Soil, Air, Water 40, no. 5 (January 23, 2012): 531–37. http://dx.doi.org/10.1002/clen.201100216.

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Zhao, Cunliang, Shenjun Qin, Yinchao Yang, Yanheng Li, and Mingyue Lin. "Concentration of Gallium in the Permo-Carboniferous Coals of China." Energy Exploration & Exploitation 27, no. 5 (October 2009): 333–43. http://dx.doi.org/10.1260/0144-5987.27.5.333.

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Gallium is widely used in electronic industry and its current price is about 500 US dollars pro kilogram. It has been found that its contents are very high in Permo-Carboniferous coal of China. In order to look for valuable associated gallium deposits in coal, gallium contents of 177 coal samples were determined by using inductively coupled plasma-mass spectrometry (ICP-MS) and the data of 873 coal samples from Chinese Permo-Carboniferous coalfields were collected. The results show that the average gallium concentration of Chinese Permo-Carboniferous coals is 15.49μg·g−1. There are two concentration types of gallium in Chinese Permo-Carboniferous coals: One type is that gallium has enriched to an ore deposit, and another type is that gallium is locally enriched in coal seams, but has not formed a valuable associated gallium ore deposit. The gallium concentration in Chinese Permo-Carboniferous coal may have several different sources: concentration in sedimentation stage, magmatic hydrothermal inputs and low-temperature hydrothermal fluids.

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Swami, Monika, and Kinjal Patel. "Need of Gallium Recovery from Waste Samples: A Review." Journal of Ravishankar University (PART-B) 34, no. 1 (May 24, 2021): 09–18. http://dx.doi.org/10.52228/jrub.2021-34-1-2.

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Gallium is an vital rare metal mainly because of its growing demand in different domain of life. It has wide applications. Gallium is considered as the backbone of the electronics industry. The supply and demand of gallium-bearing products has gradually increased during the past decade. Therefore, from the environmental stand point the need for sensitive and reliable methods for determining trace concentrations of gallium has become apparent in various fields. Gallium has become increasingly popular as a substrate material for electronic devices. Aside from ore, gallium can be obtained from such industrial sources as the Bayer process caustic liquor that is a byproduct of bauxite processing, flue dust removed from the fume-collection system in plants that produce aluminum by the electrolytic process, zinc refinery residues, gallium scrap materials, and coal fly ash. The purification process for gallium can start with solvent-extraction processes where the concentrations of impurities, especially metals, are reduced to the ppm range. The main aim of this paper is to simply put up the salient facts regarding gallium and identify applicable sources of information thereby one may create a suitable environment for the development of methods for the production of gallium via leaching through various waste samples.

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Yuanlong, Chen. "The Optimizations of MOSFET Contents in EE Undergraduate Course by using the Third Generation Semiconductor (Gallium Nitride)." E3S Web of Conferences 198 (2020): 01025. http://dx.doi.org/10.1051/e3sconf/202019801025.

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Recently, the third generation semiconductor Gallium Nitride based electrical devices earn a more and more popular status in the industry for its easy popularization and cost effectivity. And another reason is the MOSFET with Gallium Nitride applied in power switching. However, transistors-related EE major (Electronic and Electrical engineering) courses are still focusing on the old silicon-based transistors, which own many deficiencies. In this paper, the current status of Gallium Nitride based MOSFET is investigated. Besides, a comparison in conducting capability, sensitivity and power efficiency between the MOSFET IRF510 and the Gallium Nitride based product GS-065-008-1-L is carried out. After the comparison, the application of MOSFET in EE courses is suggested and the priorities and difficulties are discussed as well.

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Alliata, D., N. Anderson, M. Durand de Gevigney, I. Bergoend, and P. Gastaldo. "How to secure the fabrication of Gallium Nitride on Si wafers." International Symposium on Microelectronics 2019, no. 1 (October 1, 2019): 000444–49. http://dx.doi.org/10.4071/2380-4505-2019.1.000444.

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Abstract Process control solutions to secure the High-Volume Manufacturing of Gallium Nitride (GaN) devices for power applications are a must today. Unity recently developed and introduced on the market a total control solution that address both defectivity and metrology needs of GaN industry. Proprietary technologies like Phase Shift Deflectometry, darkfield inspection, confocal chromatic imaging and infrared interferometry are here explored to detect killer defects potentially affecting the gallium nitride wafer. More in detail, we characterized Gallium nitride on Silicon substrate before and after the fabrication of the final device and demonstrated how the fabrication process can be optimized.

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Pan, Kefeng, Ying Li, Jiawei Zhang, and Qing Zhao. "A Facile and Low-Cost Method to Produce Ultrapure 99.99999% Gallium." Materials 11, no. 11 (November 17, 2018): 2308. http://dx.doi.org/10.3390/ma11112308.

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As one of the critical raw materials, very pure gallium is important for the semiconductor and photoelectric industry. Unfortunately, refining gallium to obtain a purity that exceeds 99.99999% is very difficult. In this paper, a new, facile and efficient continuous partial recrystallization method to prepare gallium of high purity is investigated. Impurity concentrations, segregation coefficients, and the purification effect were measured. The results indicated that the contaminating elements accumulated in the liquid phase along the crystal direction. The order of the removal ratio was Cu > Mg > Pb > Cr > Zn > Fe. This corresponded to the order of the experimentally obtained segregation coefficients for each impurity: Cu < Mg < Pb < Cr < Zn < Fe. The segregation coefficient of the impurities depended strongly on the crystallization rate. All observed impurity concentrations were substantially reduced, and the purity of the gallium obtained after our refinement exceeded 99.99999%.

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Lécuyer, Christophe, and Takahiro Ueyama. "The Logics of Materials Innovation." Historical Studies in the Natural Sciences 43, no. 3 (November 2012): 243–80. http://dx.doi.org/10.1525/hsns.2013.43.3.243.

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This article examines the rise of gallium nitride as a major semiconductor material at the center of a new industry, solid-state lighting. It argues that the development of gallium nitride was shaped by the interplay of three contextual logics: material logic (the materiality of substances, tools, and fabrication techniques); market logic (the needs, demands, and interests of intended users); and competitive logic (the competitive tensions among laboratories, firms, and nations). For nearly forty years, chemists, physicists, and engineers in the United States and Japan struggled with the persistent material challenges presented by gallium nitride to meet the needs of potential markets in lighting and consumer electronics. Competition among firms and the technological and economic rivalry between the U.S. and Japan led to significant material developments and to the shaping of gallium nitride into a critical material for the manufacture of light emitting diodes. This article is intended to contribute to recent interest in the history of advanced materials and to the larger question of the determinants of innovation in technoscience.

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Huang, Chi-Yo, Pei-Han Chung, Joseph Shyu, Yao-Hua Ho, Chao-Hsin Wu, Ming-Che Lee, and Ming-Jenn Wu. "Evaluation and Selection of Materials for Particulate Matter MEMS Sensors by Using Hybrid MCDM Methods." Sustainability 10, no. 10 (September 27, 2018): 3451. http://dx.doi.org/10.3390/su10103451.

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Air pollution poses serious problems as global industrialization continues to thrive. Since air pollution has grave impacts on human health, industry experts are starting to fathom how to integrate particulate matter (PM) sensors into portable devices; however, traditional micro-electro-mechanical systems (MEMS) gas sensors are too large. To overcome this challenge, experts from industry and academia have recently begun to investigate replacing the traditional etching techniques used on MEMS with semiconductor-based manufacturing processes and materials, such as gallium nitride (GaN), gallium arsenide (GaAs), and silicon. However, studies showing how to systematically evaluate and select suitable materials are rare in the literature. Therefore, this study aims to propose an analytic framework based on multiple criteria decision making (MCDM) to evaluate and select the most suitable materials for fabricating PM sensors. An empirical study based on recent research was conducted to demonstrate the feasibility of our analytic framework. The results provide an invaluable future reference for research institutes and providers.

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12

Ganiev, I. N., F. A. Aliev, H. O. Odinazoda, A. M. Safarov, and J. H. Jayloev. "Heat capacity and thermodynamic functions of aluminum conductive alloy E-AlMgSi (Aldrey) doped with gallium." Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering 22, no. 3 (January 19, 2020): 219–27. http://dx.doi.org/10.17073/1609-3577-2019-3-219-227.

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Aluminum — a metal whose scope of application is constantly expanding. At present, aluminum and its alloys in a number of areas successfully displace traditionally used metals and alloys. The widespread use of aluminum and its alloys is due to its properties, among which, first of all, low density, satisfactory corrosion resistance and electrical conductivity, ability to apply protective and decorative coatings should be mentioned. All this, combined with the large reserves of aluminum in the earth’s crust, makes the production and consumption of aluminum very promising. One of the promising areas for the use of aluminum is the electrical industry. Conductive aluminum alloys type E-AlMgSi (Aldrey) are representatives of this group of alloys.One of the promising areas for the use of aluminum is the electrical industry. Conducting aluminum alloys of the E-AlMgSi type (Aldrey) are representatives of this group of alloys. The paper presents the results of a study of the temperature dependence of heat capacity, heat transfer coefficient, and thermodynamic functions of an aluminum alloy E-AlMgSi (Aldrey) with gallium. Research conducted in the “cooling” mode. It is shown that the temperature capacity and thermodynamic functions of the E-AlMgSi alloy (Aldrey) with gallium increase, while the Gibbs energy decreases. Gallium additives up to 1 wt.% Reduce the heat capacity, enthalpy, and entropy of the initial alloy and increase the Gibbs energy.

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13

Chen, Hong Wen. "Exposure and Health Risk of Gallium, Indium, and Arsenic from Semiconductor Manufacturing Industry Workers." Bulletin of Environmental Contamination and Toxicology 78, no. 1 (March 13, 2007): 5–9. http://dx.doi.org/10.1007/s00128-007-9037-6.

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14

Chen, H. W. "Exposure and Health Risk of Gallium, Indium, and Arsenic from Semiconductor Manufacturing Industry Workers." Bulletin of Environmental Contamination and Toxicology 78, no. 2 (April 6, 2007): 123–27. http://dx.doi.org/10.1007/s00128-007-9079-9.

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15

Ganiev, Izatullo N., Firdavs A. Aliev, Haydar O. Odinazoda, Ahror M. Safarov, and Jamshed H. Jayloev. "Heat capacity and thermodynamic functions of E-AlMgSi (Aldrey) aluminum conductor alloy doped with gallium." Modern Electronic Materials 6, no. 1 (March 30, 2020): 25–30. http://dx.doi.org/10.3897/j.moem.6.1.55277.

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Aluminum is a metal having permanently broadening applications. Currently aluminum and its alloys successfully replace conventional metals and alloys in a number of application fields. The wide use of aluminum and its alloys is primarily stipulated by its advantageous properties e.g. low density, high corrosion resistance and electrical conductivity as well as the possibility of applying protective and decorative coatings. In combination with great abundance and relatively low cost which has been almost constant in recent years, this permanently broadens the application range of aluminum. The electrochemical industry is one of the promising application fields of aluminum. The E-AlMgSi type (Aldrey) conductor aluminum alloy has high strength and ductility. This alloy acquires high electrical conductivity upon appropriate heat treatment. Products made from it are used almost exclusively for overhead power lines. This work presents data on the temperature dependence of heat capacity, heat conductivity and thermodynamic functions of the E-AlMgSi (Aldrey) aluminum alloy doped with gallium. The studies have been carried out in "cooling" mode. It has been shown that with an increase in temperature the heat capacity and thermodynamic functions of E-AlMgSi (Aldrey) alloy doped with gallium increase while the Gibbs energy decreases. Gallium doping to 1 wt.% reduces the heat capacity, enthalpy and entropy of the initial alloy and increases the Gibbs energy.

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Liao, Y. H., H. S. Yu, C. K. Ho, M. T. Wu, C. Y. Yang, J. R. Chen, and C. C. Chang. "Biological Monitoring of Exposures to Aluminium, Gallium, Indium, Arsenic, and Antimony in Optoelectronic Industry Workers." Journal of Occupational and Environmental Medicine 46, no. 9 (September 2004): 931–36. http://dx.doi.org/10.1097/01.jom.0000137718.93558.b8.

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17

Iov, Tatiana, Mihnea Costescu, Madalina Diac, Daniel Tabian, Sofia Mihaela David, Anton Knieling, and Simona Irina Damian. "Dangerous Chemical Agents: General and Odonto-Stomatological Aspects with Importance in Forensic Toxicology." Revista de Chimie 70, no. 5 (June 15, 2019): 1829–34. http://dx.doi.org/10.37358/rc.19.5.7225.

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In the heavy and light industry, the food and pharmaceutical industry, there are chemicals that contain metals with high toxic potential. Toxicity of metals is due to the harmful effect in certain forms and doses. Some metals become toxic when they form soluble compounds or in a certain chemical structure at certain doses (eg lead, mercury and candium). Not only heavy metals are toxic metals, there are also light metals that can become toxic, some of which are essential elements (iron, selenium, copper, chromium, zinc) and metals used therapeutically in medicine (aluminum, bismuth, gold, gallium, lithium and silver) may have negative effects when administered in large quantities or the elimination from the human body is deficient. Metal poisoning occurs through nutrition, medication, environmental factors. Most professional pollutants with intraoral manifestations appear in the heavy industry. The oral cavity is an entry gate for various toxic pathogens, so intoxications can be detected early due to the manifestations inside the mouth.

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Yang, Yin Dong, Paul Wu, Jason Deng, Mansoor Barati, and Alex McLean. "Developments of Solar Cell Materials and Fabrication Technology and their Effects on Energy Conversion Efficiency." Applied Mechanics and Materials 378 (August 2013): 293–301. http://dx.doi.org/10.4028/www.scientific.net/amm.378.293.

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This paper reviews the present status and future developments of solar cell materials for photovoltaic (PV) application. The solar cell made from different materials, such as silicon with different structures, cadmium telluride (CdTe), gallium arsenide GaAs), copper indium gallium diselenide (CIGS) and polymers are compared in theoretical ability, energy conversion efficiency, production and maintenance costs as well as environmental effects. Several important strategies to improve energy efficiency, such as anti-reflective coating (ARC), multi-junction concentrator and black silicon technique that improve the light-trapping and absorption properties of solar cells, are discussed. The review results show that the most efficient solar cells achieved 50% energy conversion, whereas silicon-based PV cells can reach 27%. Today the market is dominated by crystalline silicon in multi-crystalline and mono-crystalline forms due to it being the second most abundant element on the earths crust, and its nontoxic and environmental-friendly nature compared with other materials. Development of a new process with low cost, high efficiency and environment-friendly nature to produce solar grade silicon is of significant importance for the PV industry.

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Kim, Jihyun, F. Ren, and S. J. Pearton. "Will surface effects dominate in quasi-two-dimensional gallium oxide for electronic and photonic devices?" Nanoscale Horizons 4, no. 6 (2019): 1251–55. http://dx.doi.org/10.1039/c9nh00273a.

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The ultra-wide band gap semiconductor Ga₂O₃ has advantages for power electronics applications in the automotive industry, data center power management and industrial systems but attention must be paid to its surface sensitivity to the environment.

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Liao, Yen-Hsiung, Long-Chih Hwang, Jing-Shwu Kao, Shuenn-Jiun Yiin, Shu-Fang Lin, Chia-Hong Lin, Yu-Cheng Lin, and Tar-Ching Aw. "Lipid Peroxidation in Workers Exposed to Aluminium, Gallium, Indium, Arsenic, and Antimony in the Optoelectronic Industry." Journal of Occupational and Environmental Medicine 48, no. 8 (August 2006): 789–93. http://dx.doi.org/10.1097/01.jom.0000229782.71756.8e.

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21

Nagarani, S., M. Jayachandran, and C. Sanjeeviraja. "Review on Gallium Zinc Oxide Films: Material Properties and Preparation Techniques." Materials Science Forum 671 (January 2011): 47–68. http://dx.doi.org/10.4028/www.scientific.net/msf.671.47.

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Thin films continue to become more and more integral to numerous applications in today's advancing technologies. In recent years, thin film science has grown world-wide into a major research area. The importance of coatings and the synthesis of new materials for industry have resulted in a tremendous increase of innovative thin film processing technologies. Thin film properties are strongly dependent on the method of deposition, the substrate temperature, the rate of deposition, the background pressure etc. Hardness, adhesion, non porosity, high mobility of charge carriers / insulating properties and chemical inertness, which are possible with a selection of suitable functional materials and deposition techniques. There are number of different techniques that facilitate the deposition of stable thin films of oxide materials on suitable substrates. Material properties of gallium zinc oxide thin films and all the techniques used to deposit thin films are summarized with an elaborative account along with our results.

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22

Lee, Ching-Hwa, Hang-Yi Lin, Elon I. Cadogan, Srinivasa R. Popuri, and Chia-Yuan Chang. "Biosorption Performance of Biodegradable Polymer Powders for the Removal of Gallium(III) ions from Aqueous Solution." Polish Journal of Chemical Technology 17, no. 3 (September 1, 2015): 124–32. http://dx.doi.org/10.1515/pjct-2015-0060.

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Abstract Gallium (Ga) is considered an important element in the semiconducting industry and as the lifespan of electronic products decrease annually Ga-containing effluent has been increasing. The present study investigated the use of biodegradable polymer powders, crab shell and chitosan, in the removal of Ga(III) ions from aqueous solution. Ga(III) biosorption was modeled to Lagergren-first, pseudo-second order and the Weber-Morris models. Equilibrium data was modeled to the Langmuir, Freundlich and Langmuir-Freundlich adsorption isotherms to determine the probable biosorption behavior of Ga(III) with the biosorbents. The biosorbents were investigated by Fourier Transform Infrared Spectroscopy, X-ray Diffraction and Scanning Electron Microscopy/Energy Dispersive Spectra analysis.

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Feng, Zhe, Xin Liu, Yu Wang, and Changgong Meng. "Recent Advances on Gallium-Modified ZSM-5 for Conversion of Light Hydrocarbons." Molecules 26, no. 8 (April 13, 2021): 2234. http://dx.doi.org/10.3390/molecules26082234.

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Light olefins are key components of modern chemical industry and are feedstocks for the production of many commodity chemicals widely used in our daily life. It would be of great economic significance to convert light alkanes, produced during the refining of crude oil or extracted during the processing of natural gas selectively to value-added products, such as light alkenes, aromatic hydrocarbons, etc., through catalytic dehydrogenation. Among various catalysts developed, Ga-modified ZSM-5-based catalysts exhibit superior catalytic performance and stability in dehydrogenation of light alkanes. In this mini review, we summarize the progress on synthesis and application of Ga-modified ZSM-5 as catalysts in dehydrogenation of light alkanes to olefins, and the dehydroaromatization to aromatics in the past two decades, as well as the discussions on in-situ formation and evolution of reactive Ga species as catalytic centers and the reaction mechanisms.

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Jain, Rohan, Siyuan Fan, Peter Kaden, Satoru Tsushima, Harald Foerstendorf, Robert Barthen, Falk Lehmann, and Katrin Pollmann. "Recovery of gallium from wafer fabrication industry wastewaters by Desferrioxamine B and E using reversed-phase chromatography approach." Water Research 158 (July 2019): 203–12. http://dx.doi.org/10.1016/j.watres.2019.04.005.

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Sturgill, J. A., J. T. Swartzbaugh, and P. M. Randall. "Pollution prevention in the semiconductor industry through recovery and recycling of gallium and arsenic from gaas solid wastes." Clean Technologies and Environmental Policy 1, no. 4 (December 2, 1999): 248–56. http://dx.doi.org/10.1007/s100980050038.

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Sturgill, J. A., J. T. Swartzbaugh, and P. M. Randall. "Pollution prevention in the semiconductor industry through recovery and recycling of gallium and arsenic from GaAs polishing wastes." Clean Products and Processes 2, no. 1 (May 4, 2000): 0018–27. http://dx.doi.org/10.1007/s100980050047.

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Vambol, S., V. Vambol, Y. Suchikova, I. Bogdanov, and O. Kondratenko. "Investigation of the porous GaP layers' chemical composition and the quality of the tests carried out." Journal of Achievements in Materials and Manufacturing Engineering 2, no. 86 (February 1, 2018): 49–60. http://dx.doi.org/10.5604/01.3001.0011.8236.

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Purpose: The purpose of this study is to establish the quality of tests for determining the chemical composition of the porous surface obtained by the method of electrochemical etching, based on the indicators of convergence and reproducibility of the results. Design/methodology/approach: The method of electrochemical etching was used to obtain layers of porous gallium phosphide, which can be used as buffer layers for nitrides formation on their basis. Por-GaP was formed in a solution of hydrofluoric acid at a current density of j =100 mA/cm2, etching was carried out for 20 minutes. The resulting structures sulfide passivation was carried out, thus avoiding the formation of an oxide film on the samples surfaces. For this purpose, porous gallium phosphide samples were kept in a sulfide solution for 10 minutes and dried in a stream of nitrogen. The chemical composition of the porous GaP surface layers has been investigated. To do this, the method of electronprobe INCA Energy microanalysis was used. The research was carried out on the entire surface of the sample in order to calculate the total spectrum of the elemental composition of the sample under study. Findings: It was established that during anodizing, the stoichiometry of the crystals investigated did not shift significantly towards the excess of gallium atoms. Oxygen is present at an insignificant concentration of 0.3%. This indicates the effectiveness of conducting the sulfide passivation of the sample surface following the electrochemical treatment. The presence of fluorine atoms that appeared on the surface as a result of the reaction with the electrolyte during etching, is observed in extremely low concentration. Experimental studies have shown that the sample chosen can be used as a standard enterprise sample when analyzing the chemical composition of the surface of porous gallium phosphide due to its convergence, reproducibility, homogeneity. In addition, the given method for determining the standard sample can be applied to other porous semiconductors. Conducting such studies is an important technological task that will allow us to create a series of standard samples of porous semiconductors of A3B5 group. Research limitations/implications: The research was carried out for porous gallium phosphide samples synthesized in the solution of hydrofluoric acid, though, carrying out of similar experiments for por-GaP obtained in other conditions, is necessary. Practical implications: The studies of the reproducibility and convergence of the experiment have an important practical significance, since it is the reproducibility of the experiment results that is the main problem to modern material science, all the more to nanoengineering. Therefore, the technique proposed, will allow the synthesis of por-GaP layers with adjustable properties, will facilitate their widespread implementation in the real sectors of industry. The obtained porous layers can be used as standard samples. Originality/value: The main problem in the nanostructures synthesis is the adjustability of properties. The technique presented allows to form stable layers of the porous gallium phosphide with the surface chemical composition known in advance. In addition, carrying out the sulfide passivation allows to stabilize por-GaP properties, which is an important process task. For the first time, a study of the presented technique as to convergence, reproducibility and homogeneity, was conducted.

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Kulchitsky, Nikolay A., Arkady V. Naumov, and Vadim V. Startsev. "Photonic and Terahertz applications as the next gallium arsenide market driver." Modern Electronic Materials 6, no. 3 (September 30, 2020): 77–84. http://dx.doi.org/10.3897/j.moem.6.3.63224.

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Analysis of current GaAs and related device market initiated in a number of earlier works has been continued. Binary semiconductor GaAs compound is a conventional MW electronics material. Until recently GaAs based HF ICs for mobile phones were among the most rapidly growing segments of GaAs market. However the GaAs market development trend is changing. Photonics and Terahertz engineering are becoming the new world GaAs market drivers. This means that the current emphasize of GaAs single crystal technologies will shift toward vertical directional crystallization of “optoelectronic quality” crystals. In the medium and longer terms the world GaAs wafer and epitaxial structure markets will continue growing. In the shorter term we all will have to take into account COVID epidemic consequences. Still the GaAs market is closely related to Smartphone market novelties. Quite probably after a long growth period the GaAs market will keep on shrinking for the second consecutive year: GaAs production may decline by 11–12% in 2020. Assuming that the epidemic will be somehow taken under control in 2021 the overall Smartphone production can probably be expected to grow starting from 2021. Currently the Russian market of semiconductor compounds for photonics and electronic components (GaAs etc.) is but moderate and in predictable terms is not expected to achieve a level that is required for the emergence of a competitive domestic manufacturer, even though all importation replacement programs are accomplished. Meanwhile there is understanding that developing an advanced electronic components industry in Russia requires larger production of source materials.

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Kulchitskiy, N. A., A. V. Naumov, and V. V. Startsev. "Photonic and terahertz applications as a next driver of gallium arsenide market." Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering 23, no. 3 (November 10, 2020): 167–76. http://dx.doi.org/10.17073/1609-3577-2020-3-167-176.

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Analysis of current GaAs and related device market initiated in a number of earlier works has been continued. Binary semiconductor GaAs compound is a conventional MW electronics material. Until recently GaAs based HF ICs for mobile phones were among the most rapidly growing segments of GaAs market. However the GaAs market development trend is changing. Photonics and TeraHertz engineering are becoming the new world GaAs market drivers. This means that the current emphasize of GaAs single crystal technologies will shift toward vertical directional crystallization of “optoelectronic quality” crystals. In the medium and longer terms the world GaAs wafer and epitaxial structure markets will continue growing. In the shorter term we all will have to take into account COVID epidemic consequences. Still the GaAs market is closely related to Smartphone market novelties. Quite probably after a long growth period the GaAs market will keep on shrinking for the second consecutive year: GaAs production may decline by 11–12 % in 2020. Assuming that the epidemic will be somehow taken under control in 2021 the overall Smartphone production can probably be expected to grow starting from 2021.Currently the Russian market of semiconductor compounds for photonics and electronic components (GaAs etc.) is but moderate and in predictable terms is not expected to achieve a level that is required for the emergence of a competitive domestic manufacturer, even though all importation replacement programs are accomplished. Meanwhile there is understanding that developing an advanced electronic components industry in Russia requires larger production of source materials.

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Baek, Seung Yub, Jin Ho Chu, and Sung Taek Jung. "A Study on Fabrication of Ultra-Precision Diamond Tool and Length Optimization for Improving the Stability." Key Engineering Materials 777 (August 2018): 289–93. http://dx.doi.org/10.4028/www.scientific.net/kem.777.289.

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A tool for fabricating micro/nanopatterns was utilized in space optics, virtual reality, augmented reality, and semiconductor industry. Nowadays, demand of manufacturing technique for ultra-precision is continuously increasing virtual reality and augmented reality industry across the board and core technique for manufacturing next generation lens is cutting tool fabricating technique with nanoscale. In particular, tools of micro/nanosize for ultra-precision machining was made by using an ultra-precision grinding, but it was difficult to fabricate tools which have under micro scale. Recently, results of studies with many researchers were pulsed laser ablation, electric discharge machining and precision grinding. However, previous studies are unsuitable in making tools of micro/nanoscale. Due to unique physical properties of diamond, it can be easily controlled by using focused ion beam. The surface properties of the diamond layer are affected because of the amorphous damage caused by the FIB gallium ions collision, implantation and these effects can make to be able to control the geometry of cutting tool. In this study, we carried out in fabricating diamond tools under micro scale by using FIB milling through various process studies and determined in order to optimize the length of unstable tool.

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Jain, Rohan, Francesca Cirina, Peter Kaden, and Katrin Pollmann. "Investigation of the Ga Complexation Behaviour of the Siderophore Desferrioxamine B." Solid State Phenomena 262 (August 2017): 643–46. http://dx.doi.org/10.4028/www.scientific.net/ssp.262.643.

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Gallium (Ga) is a critical element for the electronic industry, however, its long-term supply is not assured. Thus, the recovery of Ga from industrial wastewaters is important. Selective sorption is a recommended technology for the recovery of Ga from industrial wastewaters, however, selective sorbents are elusive. Desferrioxamine B (DFOB), a hydroxomate siderophore that is known to be highly selective towards Fe3+, is tested for its ability to complex Ga. This study demonstrated that DFOB forms 1:1 complex with Ga and the maximum Qe-Ga is 124.4 mg of Ga complexed per g of DFOB. Further, the complexation mechanism of Ga3+ and Fe3+ with DFOB is similar, as indicated by NMR, suggesting that the selectivity of DFOB towards Fe3+ will be extended to Ga3+ as well. Thus, DFOB seems to be a suitable candidate for the sorption of Ga from industrial wastewaters.

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Swain, Basudev, Chinmayee Mishra, Leeseung Kang, Kyung-Soo Park, Chan Gi Lee, and Hyun Seon Hong. "Recycling process for recovery of gallium from GaN an e-waste of LED industry through ball milling, annealing and leaching." Environmental Research 138 (April 2015): 401–8. http://dx.doi.org/10.1016/j.envres.2015.02.027.

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Kostjuk, Sergei V. "Complexes of aluminum, iron(III), and gallium(III) chlorides with ethers in synthesis of highly reactive polyisobutylene." Journal of the Belarusian State University. Chemistry, no. 2 (August 23, 2020): 50–62. http://dx.doi.org/10.33581/2520-257x-2020-2-50-62.

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In this review, the latest achievements in the field of cationic polymerization of isobutylene catalyzed by the complexes of conventional Lewis acids with ethers are presented. The experimental and computational data on the influence of steric structure and basicity of ether used for the preparation of the Lewis acid-ether complex on the catalyst activity and regioselectivity of β-H abstraction are discussed here. Complexes of metal halides with linear (Bu2O) and moderately branched (iPr2O) ethers of moderate basicity (pKa from –4.3 to –5.4) displayed the highest activity and regioselectivity in the cationic polymerization of isobutylene affording highly reactive polyisobutylene (HR PIB) – the key intermediate in the preparation of motor oil and fuel additives. The review is also focusing on the adaptation of the developed catalytic system to the industry, which consists in using non-polar hydrocarbon solvents, high temperatures and monomer concentrations.

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Cairney, Julie M., and Paul R. Munroe. "Redeposition Effects in TEM Sample Preparation of Feal-Based Metal Matrix Composites using the Focused Ion Beam Miller." Microscopy and Microanalysis 6, S2 (August 2000): 514–15. http://dx.doi.org/10.1017/s1431927600035066.

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The focused ion beam miller (FIB) has been widely used in the semiconductor industry for many years, but only recently has its potential as a tool for materials science been recognised. The FIB uses a highly energetic beam of gallium ions to sputter material such that it can precisely section, as well as image, areas of interest. The FIB can be used to create crosssections, which can be examined in the FIB or in a scanning electron microscope (SEM). Cross sections can be made from delicate samples or samples in which a specific area needs to be viewed, for example to check the thickness of coatings or for failure analysis.The FIB may also be used to prepare transmission electron microscope (TEM) specimens [1]. Extremely site-specific thin areas may be prepared with high positional accuracy from heterogeneous samples such as composites or layered structures.

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Kaessner, S., M. G. Scheibel, S. Behrendt, B. Boettge, and K. G. Nickel. "Reliability of Novel Ceramic Encapsulation Materials for Electronic Packaging." International Symposium on Microelectronics 2018, no. 1 (October 1, 2018): 000425–33. http://dx.doi.org/10.4071/2380-4505-2018.1.000425.

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Abstract Enhancements on power electronic systems with reduced chip area and miniaturized passive components are subject of several research activities in academics and industry. To realize such future electronic devices, it is necessary to incorporate wide bandgap semiconductor technology such as silicon carbide and gallium nitride operating at higher temperatures. Therefore, the development of novel materials with high thermal conductivities and stability, withstanding harsh environments up to 300°C is of major interest. Especially, polymeric encapsulation materials have to be improved because of common degradation effects above 175°C. Ceramic (nonpolymeric) materials with thermal conductivities above 5 W/(m·K) already illustrated promising results for the encapsulation of power electronics. The present work illustrates recent developments and improvements on novel ceramic encapsulation materials, which finally avoid critical interactions with the chip surface. Furthermore, advances in reliability will be discussed in terms of passed high-temperature reverse bias and humidity tests correlated with relevant material properties.

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Kaessner, Stefan, Markus G. Scheibel, Stefan Behrendt, Bianca Boettge, Christoph Berthold, and Klaus G. Nickel. "Reliability of Novel Ceramic Encapsulation Materials for Electronic Packaging." Journal of Microelectronics and Electronic Packaging 15, no. 3 (July 1, 2018): 132–39. http://dx.doi.org/10.4071/imaps.661015.

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Abstract Enhancements on power electronic systems with reduced chip area and miniaturized passive components are subject of several research activities in academics and industry. To realize such future electronic devices, it is necessary to incorporate wide bandgap semiconductor technology such as silicon carbide and gallium nitride operating at higher temperatures. Therefore, the development of novel materials with high thermal conductivities and stability, withstanding harsh environments up to 300°C is of major interest. Especially, polymeric encapsulation materials have to be improved because of common degradation effects above 175°C. Ceramic (nonpolymeric) materials with thermal conductivities above 5 W/(m·K) already illustrated promising results for the encapsulation of power electronics. The present work illustrates recent developments and improvements on novel ceramic encapsulation materials, which finally avoid critical interactions with the chip surface. Furthermore, advances in reliability will be discussed in terms of passed high-temperature reverse bias and humidity tests correlated with relevant material properties.

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Cairney, J. M., R. D. Smith, and P. R. Munroe. "Transmission Electron Microscope Specimen Preparation of Metal Matrix Composites Using the Focused Ion Beam Miller." Microscopy and Microanalysis 5, S2 (August 1999): 892–93. http://dx.doi.org/10.1017/s1431927600017785.

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The focused ion beam (FIB) miller has been widely accepted as a powerful tool in the semiconductor industry. However, it is now finding applications in more general materials science applications. The high resolution, energetic gallium ion beam can rapidly and precisely section materials to reveal their internal structure; one particularly valuable application being the preparation of thin foils for TEM examination, especially from heterogenous materials.To date, TEM sample preparation using FIBs has concentrated on semiconductor cross-sections [1], powders [2], and surface treated materials, e.g. galvanized steels [3]. However, thin foils of grossly heterogeneous materials, such as metal-matrix composites, are also difficult to prepare using conventional methods and are therefore well suited to sectioning using the FIB. In this study, thin foils were prepared from two composite materials: a 7075 aluminium alloy containing a 20% volume fraction of SiC particles and a FeAl alloy containing a 60% volume fraction of WC particles.

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Hing, H. L., C. Burkhardt, P. Gnauck, S. Sally, H. Gelderbloms, Y. Muranaka, M. A. Kaswandi, A. H. A. Azizl, and A. Z. Sahalan. "Applications of Focused Ion Beam (FIB) on Yeast Cell & SARS Virus." Microscopy Today 15, no. 5 (September 2007): 42–43. http://dx.doi.org/10.1017/s1551929500061241.

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The focused ion beam (FIB) is a relatively novel technique to biomedical electron microscopy as it open up new means for the observations and examinations of a wide range of biomedical and biological materials. The focused ion beam, or FIB tool has been utilized mainly in the fields of material sciences and industry. The (FIB) uses high-energy gallium ions to precisely and accurately section or mill samples. Lately FIB method have been used to prepare biological samples such as yeast cells and virus particles. Yeast cells Schwanniomyces occidentalis S. occidentalis were prepared by vacuum sucking them into cellulose tubing, plunge freezing them in liquid nitrogen, followed by chemical fixation in glutaraldehye and postfixed with osmium tetroxide, dehydrated in a series of ascending alcohol concentration up to absolute alcohol, then freeze dried overnight. In the case of SARS virus, the tissue culture containing virus particles was chemically fixed with glutaraldehyde, dehydrated in ascending order of alcohol concentrations and then freeze dried.

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Li, Ming, Hisham Mohamed Cassim Mohamed Anver, Yuxin Zhang, Shi-Yang Tang, and Weihua Li. "Automatic Morphology Control of Liquid Metal using a Combined Electrochemical and Feedback Control Approach." Micromachines 10, no. 3 (March 26, 2019): 209. http://dx.doi.org/10.3390/mi10030209.

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Gallium-based liquid metal alloys have been attracting attention from both industry and academia as soft, deformable, reconfigurable and multifunctional materials in microfluidic, electronic and electromagnetic devices. Although various technologies have been explored to control the morphology of liquid metals, there is still a lack of methods that can achieve precise morphological control over a free-standing liquid metal droplet without the use of mechanical confinement. Electrochemical manipulation can be relatively easy to apply to liquid metals, but there is a need for techniques that can enable automatic and precise control. Here, we investigate the use of an electrochemical technique combined with a feedback control system to automatically and precisely control the morphology of a free-standing liquid metal droplet in a sodium hydroxide solution. We establish a proof-of-concept platform controlled by a microcontroller to demonstrate the reconfiguration of a liquid metal droplet to desired patterns. We expect that this method will be further developed to realize future reconfigurable liquid metal-enabled soft robots.

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Liu, Shiqian, Keith Sweatman, Stuart McDonald, and Kazuhiro Nogita. "Ga-Based Alloys in Microelectronic Interconnects: A Review." Materials 11, no. 8 (August 8, 2018): 1384. http://dx.doi.org/10.3390/ma11081384.

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Gallium (Ga) and some of its alloys have a range of properties that make them an attractive option for microelectronic interconnects, including low melting point, non-toxicity, and the ability to wet without fluxing most materials—including oxides—found in microelectronics. Some of these properties result from their ability to form stable high melting temperature solid solutions and intermetallic compounds with other metals, such as copper, nickel, and aluminium. Ga and Ga-based alloys have already received significant attention in the scientific literature given their potential for use in the liquid state. Their potential for enabling the miniaturisation and deformability of microelectronic devices has also been demonstrated. The low process temperatures, made possible by their low melting points, produce significant energy savings. However, there are still some issues that need to be addressed before their potential can be fully realised. Characterising Ga and Ga-based alloys, and their reactions with materials commonly used in the microelectronic industry, are thus a priority for the electronics industry. This review provides a summary of research related to the applications and characterisation of Ga-based alloys. If the potential of Ga-based alloys for low temperature bonding in microelectronics manufacturing is to be realised, more work needs to be done on their interactions with the wide range of substrate materials now being used in electronic circuitry.

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Volcheck, V. S., and V. R. Stempitsky. "Numerical simulation of the sensor for toxic nanoparticles based on the heterostructure field effect transistor." Doklady BGUIR 18, no. 8 (December 27, 2020): 62–68. http://dx.doi.org/10.35596/1729-7648-2020-18-8-62-68.

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A significant rise in the mass production of products that contain nanoparticles is of growing concern due to the detection of their toxic effects on living organisms. The standard method for analyzing the toxicity of substances, including nanomaterials, is toxicological testing, which requires the substantial consumption of time and material resources. An alternative approach is to develop models that predict the effect of nanomaterials on biological systems. In both cases, for the detection of nanoparticles an effective electronic complex consisting of a sensor with high sensitivity and a data reception/processing/transmission system is necessary. In recent times, fundamental and applied research activities aimed at the application of heterostructure field-effect transistors – high electron mobility transistors–as a base for such sensors have been undertaken. The purpose of this work is to develop a technique for modeling a sensor for toxic nanoparticles based on the heterostructure field-effect transistor. The object of the research is a gallium nitride high electron mobility transistor device structure. The subject of the research is the electrical characteristics of the transistor obtained in static mode. The calculation results show that the dependence between the concentration of the toxic nanoparticles in the test medium and the polarization charge surface density could serve as a base for modeling the sensor for toxic nanoparticles based on the heterostructure field-effect transistor. The primary advantage of the proposed technique is the use of the scaling parameter intended directly for calibrating the polarization charge density in accordance with the two-dimensional electron gas concentration. The obtained results can be utilized by the electronics industry of the Republic of Belarus for developing the hardware components of gallium nitride high-frequency electronics.

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Griffiths, A. D., J. Herrnsdorf, J. J. D. McKendry, M. J. Strain, and M. D. Dawson. "Gallium nitride micro-light-emitting diode structured light sources for multi-modal optical wireless communications systems." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, no. 2169 (March 2, 2020): 20190185. http://dx.doi.org/10.1098/rsta.2019.0185.

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Gallium nitride-based light-emitting diodes (LEDs) have revolutionized the lighting industry with their efficient generation of blue and green light. While broad-area (square millimetre) devices have become the dominant LED lighting technology, fabricating LEDs into micro-scale pixels (micro-LEDs) yields further advantages for optical wireless communications (OWC), and for the development of smart-lighting applications such as tracking and imaging. The smaller active areas of micro-LEDs result in high current density operation, providing high modulation bandwidths and increased optical power density. Fabricating micro-LEDs in array formats allows device layouts to be tailored for target applications and provides additional degrees of freedom for OWC systems. Temporal and spatial control is crucial to use the full potential of these micro-scale sources, and is achieved by bonding arrays to pitch-matched complementary metal-oxide-semiconductor control electronics. These compact, integrated chips operate as digital-to-light converters, providing optical signals from digital inputs. Applying the devices as projection systems allows structured light patterns to be used for tracking and self-location, while simultaneously providing space-division multiple access communication links. The high-speed nature of micro-LED array devices, combined with spatial and temporal control, allows many modes of operation for OWC providing complex functionality with chip-scale devices. This article is part of the theme issue ‘Optical wireless communication’.

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Połedniok, Justyna, Andrzej Kita, and Piotr Zerzucha. "Spectrophotometric and Inductively Coupled Plasma–Optical Emission Spectroscopy Determination of Gallium in Natural Soils and Soils Polluted by Industry: Relationships between Elements." Communications in Soil Science and Plant Analysis 43, no. 8 (April 15, 2012): 1121–35. http://dx.doi.org/10.1080/00103624.2012.662561.

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Xiong, Fangzhu, Weiling Guo, Shiwei Feng, Xuan Li, Zaifa Du, Le Wang, Jun Deng, and Jie Sun. "Transfer-Free Graphene-Like Thin Films on GaN LED Epiwafers Grown by PECVD Using an Ultrathin Pt Catalyst for Transparent Electrode Applications." Materials 12, no. 21 (October 28, 2019): 3533. http://dx.doi.org/10.3390/ma12213533.

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In this work, we grew transfer-free graphene-like thin films (GLTFs) directly on gallium nitride (GaN)/sapphire light-emitting diode (LED) substrates. Their electrical, optical and thermal properties were studied for transparent electrode applications. Ultrathin platinum (2 nm) was used as the catalyst in the plasma-enhanced chemical vapor deposition (PECVD). The growth parameters were adjusted such that the high temperature exposure of GaN wafers was reduced to its minimum (deposition temperature as low as 600 °C) to ensure the intactness of GaN epilayers. In a comparison study of the Pt-GLTF GaN LED devices and Pt-only LED devices, the former was found to be superior in most aspects, including surface sheet resistance, power consumption, and temperature distribution, but not in optical transmission. This confirmed that the as-developed GLTF-based transparent electrodes had good current spreading, current injection and thermal spreading functionalities. Most importantly, the technique presented herein does not involve any material transfer, rendering a scalable, controllable, reproducible and semiconductor industry-compatible solution for transparent electrodes in GaN-based optoelectronic devices.

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Xi, Rui, Shao-Hui Zhang, Long Zhang, Chao Wang, Lu-Jia Wang, Jing-Hui Yan, and Ge-Bo Pan. "Electrodeposition of Pd-Pt Nanocomposites on Porous GaN for Electrochemical Nitrite Sensing." Sensors 19, no. 3 (January 31, 2019): 606. http://dx.doi.org/10.3390/s19030606.

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In recent years, nitrite pollution has become a subject of great concern for human lives, involving a number of fields, such as environment, food industry and biological process. However, the effective detection of nitrite is an instant demand as well as an unprecedented challenge. Here, a novel nitrite sensor was fabricated by electrochemical deposition of palladium and platinum (Pd-Pt) nanocomposites on porous gallium nitride (PGaN). The obtained Pd-Pt/PGaN sensor provides abundant electrocatalytic sites, endowing it with excellent performances for nitrite detection. The sensor also shows a low detection limit of 0.95 µM, superior linear ampere response and high sensitivity (150 µA/mM for 1 to 300 µM and 73 µA/mM for 300 to 3000 µM) for nitrite. In addition, the Pd-Pt/PGaN sensor was applied and evaluated in the determination of nitrite from the real environmental samples. The experimental results demonstrate that the sensor has good reproducibility and long-term stability. It provides a practical way for rapidly and effectively monitoring nitrite content in the practical application.

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Salem, Jebreel M., and Dong Sam Ha. "A High Temperature Passive GaN-HEMT Mixer for Downhole Communications." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2016, HiTEC (January 1, 2016): 000272–77. http://dx.doi.org/10.4071/2016-hitec-272.

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Abstract Declining reserves of easily accessible natural resources have motivated the oil and gas industry to drill deeper. Temperatures in these hostile wells can exceed 210 °C. Cooling and conventional heat extraction techniques are impractical in such a harsh environment. Reliable electronic designs that can sustain high temperature become necessary. This paper presents a high temperature passive RF mixer that is suited for downhole communications. The proposed mixer is designed to upconvert or downconvert the incoming signal with a low conversion loss (CL) and high linearity and reliable operation at temperature up to 250 °C. Gallium Nitride (GaN) is a wide band gap technology that can provide a reliable operation at the elevated ambient temperature, and the proposed mixer adopts a commercial GaN high electron mobility transistor (HEMT) technology. Measurement results indicate that the proposed mixer achieves CL of 6.5 dB at LO power of 2.5 dBm for the downconversion from 230–253 MHz to 97.5 MHz at 250 °C and input P1dB compression point lies at 5 dBm. The power dissipation of the mixer is virtually zero.

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Roman, Barbara, Monika Retajczyk, Łukasz Sałaciński, and Robert Pełech. "Curcumin - Properties, Applications and Modification of Structure." Mini-Reviews in Organic Chemistry 17, no. 5 (August 11, 2020): 486–95. http://dx.doi.org/10.2174/1570193x16666190621110247.

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In recent years, the interest in biologically active compounds of natural origin has increased significantly. Researchers' research focuses on increasing the activity of curcumin by forming complexes with metals such as vanadium, iron, copper or gallium. Introduction of metal compounds to curcumin increases the scope of application in pharmacology. The main direction of research development is the treatment of tumors, among others stomach cancer or leukemia. Curcuminoids are the main components of turmeric (Curcuma longa L.), a plant from India and South-East Asia. Due to its intense yellow-orange color and pleasant aroma, the powdered rootstalk is widely used in the food industry, as natural dye and spice. The chemical compound responsible for the characteristic color of rhizomes of curcuma is 1,6-heptadien-3,5-dione-1,7-bis(4-hydroxy-3-methoxyphenyl) - (1E, 6E) called curcumin. This work aims to characterize curcumin in terms of its structure, therapeutic properties and also as a substrate for the synthesis of valuable derivatives like tetrahydrocurcumin. Knowledge about this relationship based on literature analysis will enable a better understanding of the factors responsible for its biological activity.

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Annaniah, Luruthudass, and Mutharasu Devarajan. "Impact of severe cracked germanium (111) substrate on aluminum indium gallium phosphate light-emitting-diode’s electro-optical performance." Open Physics 14, no. 1 (January 1, 2016): 253–60. http://dx.doi.org/10.1515/phys-2016-0024.

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AbstractCracked die is a serious failure mode in the Light Emitting Diode (LED) industry – affecting LED quality and long-term reliability performance. In this paper an investigation has been carried out to find the correlation between severe cracked germanium (Ge) substrate of an aluminum indium gallium phosphate (AlInGaP) LED and its electro-optical performance after the Temperature Cycle (TC) test. The LED dice were indented at several bond forces using a die bonder. The indented dice were analysed using a Scanning Electron Microscope (SEM). The result showed that severe cracks were observed at 180 gF onward. As the force of indentation increases, crack formation also becomes more severe thus resulting in the chipping of the substrate. The cracked dies were packaged and the TC test was performed. The results did not show any electro-optical failure or degradation, even after a 1000 cycle TC test. Several mechanically cross-sectioned cracked die LEDs, were analysed using SEM and found that no crack reached the active layer. This shows that severely cracked Ge substrate are able to withstand a −40°C/+100°C TC test up to 1000 cycles and LED optical performance is not affected. A small leakage current was observed in all of the cracked die LEDs in comparison to the reference unit. However, this value is smaller than the product specification and is of no concern.

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Poudel, Deewakar, Shankar Karki, Benjamin Belfore, Grace Rajan, Sushma Swaraj Atluri, Sina Soltanmohammad, Angus Rockett, and Sylvain Marsillac. "Degradation Mechanism Due to Water Ingress Effect on the Top Contact of Cu(In,Ga)Se2 Solar Cells." Energies 13, no. 17 (September 2, 2020): 4545. http://dx.doi.org/10.3390/en13174545.

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The impact of moisture ingress on the surface of copper indium gallium diselenide (CIGS) solar cells was studied. While industry-scale modules are encapsulated in specialized polymers and glass, over time, the glass can break and the encapsulant can degrade. During such conditions, water can potentially degrade the interior layers and decrease performance. The first layer the water will come in contact with is the transparent conductive oxide (TCO) layer. To simulate the impact of this moisture ingress, complete devices were immersed in deionized water. To identify the potential sources of degradation, a common window layer for CIGS devices—a bilayer of intrinsic zinc oxide (i-ZnO) and conductive indium tin oxide (ITO)—was deposited. The thin films were then analyzed both pre and post water soaking. To determine the extent of ingress, dynamic secondary ion mass spectroscopy (SIMS) was performed on completed devices to analyze impurity diffusion (predominantly sodium and potassium) in the devices. The results were compared to device measurements, and indicated a degradation of device efficiency (mostly fill factor, contrary to previous studies), potentially due to a modification of the alkali profile.

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Luo, Peng, Frank Schnieder, Olof Bengtsson, Valeria Vadalà, Antonio Raffo, Wolfgang Heinrich, and Matthias Rudolph. "A streamlined drain-lag model for GaN HEMTs based on pulsed S-parameter measurements." International Journal of Microwave and Wireless Technologies 11, no. 2 (February 22, 2019): 121–29. http://dx.doi.org/10.1017/s1759078719000060.

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AbstractAccurately and efficiently modeling the drain-lag effects is crucial in nonlinear large-signal modeling for Gallium Nitride high electron mobility transistors. In this paper, a simplified yet accurate drain-lag model based on an industry standard large-signal model, i.e., the Chalmers (Angelov) model, extracted by means of pulsed S-parameter measurements, is presented. Instead of a complex nonlinear drain-lag description, only four constant parameters of the proposed drain-lag model need to be determined to accurately describe the large impacts of the drain-lag effects, e.g., drain-source current slump, typical kink observed in pulsed IV curves, and degradation of the output power. The extraction procedure of the parameters is based on pulsed S-parameter measurements, which allow to freeze traps and isolate the trapping effects from self-heating. It is also shown that the model can very accurately predict the load pull performance over a wide range of drain bias voltages. Finally, the large-signal network analyzer measurements at low frequency are used to further verify the proposed drain-lag model in the prediction of the output current in time domain under large-signal condition.

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Journal articles on the topic 'Gallium industry'

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