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Wyszukujesz frazę "gallium" wg kryterium: Temat


Tytuł:
Gallium oxide buffer layers for gallium nitride epitaxy
Autorzy:
Korbutowicz, R
Wnek, J
Panachida, P
Serafinczuk, J
Srnanek, R
Powiązania:
https://bibliotekanauki.pl/articles/174303.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
hydride vapour phase epitaxy
gallium nitride
gallium oxide
thermal oxidation
buffer layer
Opis:
Gallium nitride (GaN) is very attractive semiconductor material because of its unique properties. The serious matter is a lack of easy access to bulk crystals of GaN. Synthesized crystals are precious and rather small. For these reasons almost all device manufacturers and researchers apply alternative substrates for gallium nitride devices epitaxy and it causes that the technology is intricate. Alternative substrates need buffer layers – their technology is usually complex and expensive. We have proposed a simple method to avoid large costs: applying gallium oxide – monoclinic β-Ga2O3, as the buffer layer, which has structural properties quite good matched to GaN. As the substrates made from single crystal gallium oxide are still hardly available on the market, we have used hydride vapour phase epitaxy (HVPE) GaN epilayers as a starting material. It can be GaN layer under good quality – middle or low. The oxidation process converts top GaN to β-Ga2O3 layer which can release or absorb the strain. Applying such structure in another, second, epitaxy of GaN allows to obtain good quality epitaxial structures using HVPE technique.
Źródło:
Optica Applicata; 2013, 43, 1; 73-79
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of p-type contacts to InGaN-based laser diodes and light emitting diodes grown by plasma assisted molecular beam epitaxy
Autorzy:
Nowakowski-Szkudlarek, Krzesimir
Muziol, Grzegorz
Żak, Mikolaj
Hajdel, Mateusz
Siekacz, Marcin
Feduniewicz-Żmuda, Anna
Skierbiszewski, Czesław
Powiązania:
https://bibliotekanauki.pl/articles/173471.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
gallium nitride
molecular beam epitaxy
contacts
Opis:
We investigated the influence of the In0.17Ga0.83N:Mg contact layer grown by plasma assisted molecular beam epitaxy on the resistivity of p-type Ni/Au contacts. We demonstrate that the Schottky barrier width for p-type contact is less than 5 nm. We compare circular transmission line measurements with a p-n diode current-voltage characteristics and show that discrepancies between these two methods can occur if surface quality is deteriorated. It is found that the most efficient contacts to p-type material consist of In0.17Ga0.83N:Mg contact layer with Mg doping levelas high as 2 × 1020 cm–3.
Źródło:
Optica Applicata; 2020, 50, 2; 323-330
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Beneficiation of Ga from alunite concentrates by selective acid leaching and alkaline precipitation
Autorzy:
Zhu, Mao-Lan
Chen, Hang
Zhong, Shui-Ping
Huang, Zhong-Sheng
Chen, Xi
Hu, Zhi-Biao
Powiązania:
https://bibliotekanauki.pl/articles/110733.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
gallium
selective leaching
precipitation
alunite concentrate
Opis:
In this study beneficiation of Ga from alunite ore was investigated. The effects of the calcination temperature, H2SO4 concentration, leaching temperature and liquid-solid ratio on the dissolution characteristic of Ga, K and Al were studied. The results showed that increasing the calcination temperature, H2SO4 concentration and leaching temperature can improve the solubility of K and Al. However, higher H2SO4 concentration and lower leaching temperature can improve the dissolution of Ga, which was beneficial to recovery of Ga. On the basis of the solubility difference in H2SO4, a two-stage process of selective acid leaching and alkali precipitation of Ga was proposed. The concentration of Ga was increased significantly from 54 g/t in alunite ore to 4100 g/t in alkali precipitation product. The major elements of Al and K in alunite were recovered as the alum crystal with a purity of 99.62%.
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 4; 1028-1038
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of changes in the resistivity of semi-insulating materials
Autorzy:
Suproniuk, Marek
Powiązania:
https://bibliotekanauki.pl/articles/1849000.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
resistivity
semiconductor
gallium phosphide
silicon carbide
Opis:
Electrical properties of semiconductor materials depend on their defect structure. Point defects, impurities or admixture contained in a semiconductor material, strongly affect its properties and determine the performance parameters of devices made on its basis. The results of the currently used methods of examining the defect structure of semiconductor material are imprecise due to solution of ill-posed equations. These methods do not allow for determination of concentration of the defect centers examined. Improving the resolution of the obtained parameters of defect centers, determining their concentration and studying changes in the resistivity of semi-insulating materials can be carried out, among others, by modelling changes in the concentration of carriers in the conduction and valence bands. This method allows to determine how charge compensation in the material affects the changes in its resistivity. Calculations based on the Fermi-Dirac statistics can complement the experiment and serve as a prediction tool for identifying and characterizing defect centers. Using the material models (GaP, 4H-SiC) presented in the article, it is possible to calculate their resistivity for various concentrations of defect centers in the temperature range assumed by the experimenter. The models of semi-insulating materials presented in the article were built on the basis of results of testing parameters of defect centers with high-resolution photoinduced transient spectroscopy (HRPITS). The current research will allow the use of modelling to determine optimal parameters of semi-insulating semiconductor materials for use in photoconductive semiconductor switches (PCSS).
Źródło:
Metrology and Measurement Systems; 2021, 28, 3; 581-592
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of changes in the resistivity of semi-insulating materials
Autorzy:
Suproniuk, Marek
Powiązania:
https://bibliotekanauki.pl/articles/1849019.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
resistivity
semiconductor
gallium phosphide
silicon carbide
Opis:
Electrical properties of semiconductor materials depend on their defect structure. Point defects, impurities or admixture contained in a semiconductor material, strongly affect its properties and determine the performance parameters of devices made on its basis. The results of the currently used methods of examining the defect structure of semiconductor material are imprecise due to solution of ill-posed equations. These methods do not allow for determination of concentration of the defect centers examined. Improving the resolution of the obtained parameters of defect centers, determining their concentration and studying changes in the resistivity of semi-insulating materials can be carried out, among others, by modelling changes in the concentration of carriers in the conduction and valence bands. This method allows to determine how charge compensation in the material affects the changes in its resistivity. Calculations based on the Fermi-Dirac statistics can complement the experiment and serve as a prediction tool for identifying and characterizing defect centers. Using the material models (GaP, 4H-SiC) presented in the article, it is possible to calculate their resistivity for various concentrations of defect centers in the temperature range assumed by the experimenter. The models of semi-insulating materials presented in the article were built on the basis of results of testing parameters of defect centers with high-resolution photoinduced transient spectroscopy (HRPITS). The current research will allow the use of modelling to determine optimal parameters of semi-insulating semiconductor materials for use in photoconductive semiconductor switches (PCSS).
Źródło:
Metrology and Measurement Systems; 2021, 28, 3; 581-592
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of changes in the resistivity of semi-insulating materials
Autorzy:
Suproniuk, Marek
Powiązania:
https://bibliotekanauki.pl/articles/1849057.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
resistivity
semiconductor
gallium phosphide
silicon carbide
Opis:
Electrical properties of semiconductor materials depend on their defect structure. Point defects, impurities or admixture contained in a semiconductor material, strongly affect its properties and determine the performance parameters of devices made on its basis. The results of the currently used methods of examining the defect structure of semiconductor material are imprecise due to solution of ill-posed equations. These methods do not allow for determination of concentration of the defect centers examined. Improving the resolution of the obtained parameters of defect centers, determining their concentration and studying changes in the resistivity of semi-insulating materials can be carried out, among others, by modelling changes in the concentration of carriers in the conduction and valence bands. This method allows to determine how charge compensation in the material affects the changes in its resistivity. Calculations based on the Fermi-Dirac statistics can complement the experiment and serve as a prediction tool for identifying and characterizing defect centers. Using the material models (GaP, 4H–SiC) presented in the article, it is possible to calculatetheir resistivity for various concentrations of defect centers in the temperature range assumed by the experimenter. The models of semi-insulating materials presented in the article were built on the basis of results of testing parameters of defect centers with high-resolution photoinduced transient spectroscopy (HRPITS). The current research will allow the use of modelling to determine optimal parameters of semi-insulating semiconductor materials for use in photoconductive semiconductor switches (PCSS).
Źródło:
Metrology and Measurement Systems; 2021, 28, 3; 581-592
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cyclotron production of 68Ga via proton-induced reaction on 68Zn target
Autorzy:
Sadeghi, M.
Kakavand, T.
Rajabifar, S.
Mokhtari, L.
Rahimi-Nezhad, A.
Powiązania:
https://bibliotekanauki.pl/articles/146448.pdf
Data publikacji:
2009
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
production
gallium-68
zinc-68
PET
cyclotron
Opis:
68Ga is an important positron-emitting radionuclide for positron emission tomography. In this work 68Ga was produced via the 68Zn(p,n)68Ga nuclear reaction. 68Zn electrodeposition on a copper substrate was carried out by alkaline cyanide baths. 68Zn target was irradiated with a 15 MeV proton beam and a 150 mi A current. The production yield achieved was 136 mCi/ mi Aźh (5.032 GBq/mi Aźh). 68Ga was separated from zinc and copper by a combination of cation exchange chromatography and liquid-liquid extraction methods.
Źródło:
Nukleonika; 2009, 54, 1; 25-28
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Desorption of Argon Implanted into Gallium Arsenide
Autorzy:
Turek, Marcin
Droździel, Andrzej
Pyszniak, Krzysztof
Węgierek, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/2201837.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
thermal desorption spectroscopy
gallium arsenide
ion implantation
Opis:
Thermal desorption of Ar implanted with energies 150 keV and 100 keV with fluence 1×10^16 cm^-2 into GaAs is considered. A sudden release of Ar is observed in temperature range 1100 -1180 K as a single narrow peak in TDS (Thermal Desorption Spectroscopy) spectra. This is accompanied by a strong background signal from atmospheric Ar trapped in various parts of the spectrometer. Desorption peak shift analysis allows estimation of desorption activation energy values - these are 3.6 eV and 2.5 eV for implantation energies 150 keV and 100 keV, respectively. These results are comparable to that measured for Ar implanted into germanium target.
Źródło:
Advances in Science and Technology. Research Journal; 2022, 16, 4; 318--326
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Production and quality control of 66Ga radionuclide
Autorzy:
Sabet, M.
Rowshanfarzad, P.
Jalilian, A.
Ensaf, M.
Rajamand, A.
Powiązania:
https://bibliotekanauki.pl/articles/146278.pdf
Data publikacji:
2006
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
gallium-66
cyclotron
radiochemical separation
target recovery
Opis:
The purpose of this study was to develop the required targetry and radiochemical methods for production of 66Ga, according to its increasing applications in various fields of science. The 66Zn(p,n)66Ga reaction was selected as the best choice for the production of 66Ga. The targets were bombarded with 15 MeV protons from cyclotron (IBA-Cyclone 30) at the Nuclear Research Center for Agriculture and Medicine (NRCAM) with a current of 180 mA for 67 min. ALICE and SRIM (Stopping and Range of Ions in Matter) nuclear codes were used to predict the optimum energy and target thickness. Targets were prepared by electroplating 95.73% enriched 66Zn on a copper backing. Chemical processing was performed by a no-carrier-added method consisting of ion exchange chromatography and liquid-liquid extraction. Anion exchange chromatography was also used for the recovery of target material. Quality control of the product was carried out in two steps of chemical and radionuclide purity control. The activity of 66Ga was 82.12 GBq at EOB and the production yield was 410.6 MBq/mAh. The radiochemical separation yield was 93% and the yield of chemical recovery of the target material was 97%. Quality control tests showed a radionuclide purity higher than 97% and the amounts of chemical impurities were in accordance with the United States Pharmacopoeiae levels.
Źródło:
Nukleonika; 2006, 51, 3; 147-154
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calorimetric Measurements of Ga-Li System by Direct Reaction Method
Autorzy:
Dębski, A.
Powiązania:
https://bibliotekanauki.pl/articles/350810.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
gallium-lithium system
Ga-Li
calorimetry
thermochemistry
Opis:
The direct reaction calorimetric method was used for the determination of the formation enthalpy of alloys which concentrations correspond to the: Ga7Li2, Ga9Li5, GaLi, Ga4Li5, Ga2Li3, and GaLi2 intermetallic phases. The obtained experimental values of the formation enthalpy were: –18.1 ±0.8 kJ/mol at., –26.5 ±0.3 kJ/mol at., –34.7 ±0.3 kJ/mol at., –33.5 ±0.5 kJ/mol at., –32.8 ±0.3 kJ/mol at. and –24.6 ±1.4 kJ/mol at., respectively. After the calorimetric measurements, all the samples were checked by way of X-ray diffraction investigations to confirm the structure of the measured alloys. All the measured values of the formation enthalpy of the Ga-Li alloys were compared with literature data and the data calculated with use of the Miedema model.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2A; 919-926
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation and evaluation of a [66Ga]gallium chitosan complex in fibrosarcoma bearing animal models
Autorzy:
Pourjavadi, A.
Akhlaghi, M.
Jalilian, A. R.
Powiązania:
https://bibliotekanauki.pl/articles/147067.pdf
Data publikacji:
2011
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
chitosan
gallium-66
internal radiotherapy
fibrosarcoma
intratumoral injection
Opis:
[66Ga]gallium chitosan complex was prepared with a high radiochemical purity (greater than 99%) in dilute acetic acid solution. The radiochemical purity of [66Ga]gallium chitosan complex was checked by using paper chromatography technique. The prepared complex solution was injected intratumoral to fibrosarcoma-bearing mice and the leakage of radioactivity from injection site was investigated. Approximately, 85.4% of the injected dose was retained in the injection site 54 h after injection and most of the leaked radioactivity was accumulated in the blood, liver (0.5%) and lung (6.5%).
Źródło:
Nukleonika; 2011, 56, 1; 35-40
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biosorption Performance of Biodegradable Polymer Powders for the Removal of Gallium(III) ions from Aqueous Solution
Autorzy:
Lee, Ching-Hwa
Lin, Hang-Yi
Cadogan, Elon I.
Popuri, Srinivasa R.
Chang, Chia-Yuan
Powiązania:
https://bibliotekanauki.pl/articles/778539.pdf
Data publikacji:
2015
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
chitosan
crab shell powder
gallium
Langmuir-Freundlich
kinetics
Opis:
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.
Źródło:
Polish Journal of Chemical Technology; 2015, 17, 3; 124-132
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Uranium and neodymium partitioning in alkali chloride melts using low-melting gallium-based alloys
Autorzy:
Melchakov, S. Y.
Maltsev, D. S.
Volkovich, V. A.
Yamshchikov, L. F.
Lisienko, D. G.
Osipenko, A. G.
Rusakov, M. A.
Powiązania:
https://bibliotekanauki.pl/articles/146407.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
neodymium
uranium
gallium
separation factor
reductive extraction
pyrochemical reprocessing
Opis:
Partitioning of uranium and neodymium was studied in a ‘molten chloride salt – liquid Ga-X (X = In or Sn) alloy’ system. Chloride melts were based on the low-melting ternary LiCl-KCl-CsCl eutectic. Nd/U separation factors were calculated from the thermodynamic data as well as determined experimentally. Separation of uranium and neodymium was studied using reductive extraction with neodymium acting as a reducing agent. Efficient partitioning of lanthanides (Nd) and actinides (U), simulating fission products and fissile materials in irradiated nuclear fuels, was achieved in a single stage process. The experimentally observed Nd/U separation factor valued up to 106, depending on the conditions.
Źródło:
Nukleonika; 2015, 60, No. 4, part 2; 915-920
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Behavior of gallium and germanium associated with zinc sulfide concentrate in oxygen pressure leaching
Autorzy:
Liu, F.
Liu, Z.
Li, Y.
Wilson, B. P.
Lundstrom, M.
Powiązania:
https://bibliotekanauki.pl/articles/110812.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
zinc sulfide concentrate
gallium
germanium
pyrite
oxygen pressure leaching
Opis:
The Fankou zinc concentrate (Guangdong province, China) was mineralogically characterized and results showed that the main germanium-bearing minerals in the sample comprised of zinc sulfide and galena, whereas gallium-bearing minerals were pyrite, sphalerite and silicate. Oxygen pressure leaching of zinc sulfide concentrate was carried out in order to investigate the effect of pressure, leaching time, sulfuric acid and copper concentrations on the leaching behavior of gallium and germanium. Under optimum conditions, leaching of Zn, Fe, Ge and Ga reached 98.21, 90.45, 97.45 and 96.65%, respectively. In the leach residues, it was determined that some new precipitates, such as PbSO4, CaSO4 and SiO2, were formed, which co-precipitated a certain amount of Ga and Ge from the leach solution. The results clearly indicated that Ga and Ge were much more difficult to leach than Zn, and provided answers to why the leaching efficiency of Ga is 10% lower when compared to Ge.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 2; 1047-1060
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of photoconductive semiconductor switch parameters with selected switch devices in power systems
Autorzy:
Piwowarski, Karol
Powiązania:
https://bibliotekanauki.pl/articles/1818252.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
electronic devices
electric switch
photoconductive semiconductor switches
gallium phosphide
Opis:
Currently, work is underway to manufacture and find potential applications for a photoconductive semiconductor switch made of a semi-insulating material. The article analyzes the literature in terms of parameters and possibilities of using PCSS switches, as well as currently used switches in power and pulse power electronic system. The results of laboratory tests for the prototype model of the GaP-based switch were presented and compared with the PCSS switch parameters from the literature. The operating principle, parameters and application of IGBT transistor, thyristor, opto-thyristor, spark gap and power switch were presented and discussed. An analysis of the possibilities of replacing selected elements by the PCSS switch was carried out, taking into account the pros and cons of the compared devices. The possibility of using the currently made PCSS switch from gallium phosphide was also discussed.
Źródło:
Opto-Electronics Review; 2020, 28, 2; 74--81
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł

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