Gallium Content Research Articles

A theoretical study of the effects of electric field, hydrostatic pressure, and temperature on photoionization cross-section of a donor impurity in (Al, Ga)N/AlN double triangular quantum wells

The aim of this research is to analyze the influence of various factors on the photo-ionization cross-section in (Al, Ga)N/AlN double triangular quantum wells. Using the finite difference method, the effects of the electric field, hydrostatic pressure, temperature, and Ga concentration were investigated within the effective mass and parabolic approximations. Our findings show that the photo-ionization cross-section (PICS) is highly dependent on all the variables under consideration. The optical spectra were blue-shifted with increasing electric field and pressure and red-shifted with increasing temperature and impurity displacement far from the center of the structure. Furthermore, it was found that changes in gallium content and impurity position can increase the PICS amplitude. A comparison of the obtained results with the existing literature as a limiting case of the reported problem is also provided, and excellent agreement is found.

Serving Two Masters: Effect of Escherichia coli Dual Resistance on Antibiotic Susceptibility

The prevalence of multidrug-resistant bacteria and their increased pathogenicity has led to a growing interest in metallic antimicrobial materials and bacteriophages as potential alternatives to conventional antibiotics. This study examines how resistance to excess iron (III) influences the evolution of bacteriophage resistance in the bacterium Escherichia coli. We utilized experimental evolution in E. coli to test the effect of the evolution of phage T7 resistance on populations resistant to excess iron (III) and populations without excess iron resistance. Phage resistance evolved rapidly in both groups. Dual-resistant (iron (III)/phage) populations were compared to their controls (excess iron (III)-resistant, phage-resistant, no resistance to either) for their performance against each stressor, excess iron (III) and phage; and correlated resistances to excess iron (II), gallium (III), silver (I) and conventional antibiotics. Excess iron (III)/phage-resistant populations demonstrated superior 24 h growth compared to all other populations when exposed to increasing concentrations of iron (II, III), gallium (III), ampicillin, and tetracycline. No differences in 24 h growth were shown between excess iron (III)/phage-resistant and excess iron (III)-resistant populations in chloramphenicol, sulfonamide, and silver (I). The genomic analysis identified selective sweeps in the iron (III) resistant (rpoB, rpoC, yegB, yeaG), phage-resistant (clpX →/→ lon, uvaB, yeaG, fliR, gatT, ypjF, waaC, rpoC, pgi, and yjbH) and iron (III)/phage resistant populations (rcsA, hldE, rpoB, and waaC). E. coli selected for resistance to both excess iron (III) and T7 phage showed some evidence of a synergistic effect on various components of fitness. Dual selection resulted in correlated resistances to ionic metals {iron (II), gallium (III), and silver (I)} and several conventional antibiotics. There is a likelihood that this sort of combination antimicrobial treatment may result in bacterial variants with multiple resistances.

A data analysis method to rapidly characterize gallium concentration in plutonium matrices using LIBS

The processing of actinide samples is a complex and costly endeavor that requires compositional analysis at various stages. Laser-induced breakdown spectroscopy (LIBS) has been used to analyze actinide-containing samples in many nuclear applications including waste management, fuel processing and forensics. The LIBS spectrum obtained from actinide materials are generally extremely complex, exhibiting many thousands of strong emission lines. This makes it difficult to identify other elements within the sample of interest, given the rich and dominant actinide spectrum. In this article we describe a recent effort to identify and quantify impurities and alloying constituents in plutonium matrices using a hand-held LIBS instrument that is used to rapidly and efficiently measure an emission spectrum from a material sample. We tabulate the emission line positions and intensities of plutonium. We report the development of machine-learning software that can identify gallium and quantify its concentration in plutonium matrices. This work has the potential to provide a rapid and nearly non-destructive technique that allows more confidence in characterizing the composition of materials that are present within complex actinide associated targets. We describe how our LIBS measurements and data analysis methods have successfully quantified the gallium concentration in a variety of samples.

Seed-assisted synthesis of Ga-MFI slabs and nanocrystal agglomerates and comparative study of acidic properties

A series of Ga-MFI zeolites were one-step synthesized following the seed-assisted strategy without using additional organic template. The effects of synthesis parameters on the framework fabrication, morphology evolution, and gallium incorporation were systematically investigated by XRD, N2-adsorption, UV-Raman, STEM, TEM, solid state NMR, NH3-TPD, and Py-IR analyses. The Si/Ga seed exhibited a highly efficient structure-directing capability in the assembly of MFI framework and the amount of the costly tetrapropylammonium hydroxide (TPA+) was thus decreased to less than one-tenth in comparison with the traditional synthesis. Crystallization temperature and pre-aging conditions played the key roles in the Ga-MFI zeolite synthesis. Both of the morphology and the intraframework gallium concentration can be facilely controlled by adding the mineralizer and surfactant. The addition of NH4F and CTAB was favorable for the formation of the slabs-form product but against to the gallium substitution. Only with the help of Si/Ga seed, the synthesized Ga-MFI nanocrystal agglomerates possess a highly accessible hierarchical mesopore structure that consisted solely of interparticle-type mesopores. Simultaneously, it also exhibited a remarkable gallium incorporation, which ensured the great acidic properties, including strong acidic strength and high acid amount. As a consequence, the Ga-MFI nanocrystal agglomerates performed the excellent catalytic activity in the LDPE degradation.

The discovery of the effect of compositional disorder on the opto-electronic properties of the deformed InGaAsP quaternary

This article presents a theoretical study of the optoelectronic properties of InGaAsP alloys fabricated on three different substrates: InP, GaA, and ZnSe. Particular attention has been paid to the study of bandgap energy along points of high symmetry in the Brillouin zone, absorption coefficient, and refractive index of materials without compositional disorder and subjected to deformation. Our goal is to expand the range of optoelectronic properties. We found that the absorption coefficient of the deformed InGaAsP/InP material in the absence of disorder varies between 9.66×104cm−1 and 1.35×105cm−1 changing the content of phosphorus and gallium, making it possible to provide a wide range of refractive indices [3.06, 3.84] compared to GaAs substrates [2.67, 3.02] and ZnSe [2.69, 3.05]. This refractive index contrast can be exploited in the design of optical waveguides.

Geochemistry and organic petrography of the Middle Permian Lucaogou alkaline lacustrine oil shale in the southern Junggar Basin, China: Implications for formation conditions and organic matter accumulation

Organic matter (OM) accumulation in terrestrial sediments shows not only a significant carbon sink in the Earth's carbon cycle but an important origin of fossil fuels, which is closely associated with the complex and diverse depositional environments and climate conditions. The Junggar Basin developed the most laterally extensive and thickest alkaline lacustrine sediments as well as the richest hydrocarbon source rock/oil shale interval of all the world during the deposition of the Lucaogou Formation and equivalent units. In this study, the sedimentary succession of 564 m with a mudstone and dolomite matrix of the Lucaogou oil shale from the Qi 1 well located in the southern Junggar Basin was investigated, which can be divided into two members based on lithology. This paper is a synthetic use of major element oxides, trace, and rare-earth elements as well as organic petrography data as proxies to evaluate the provenance, paleotectonic setting, paleoclimate and weathering conditions, paleoenvironment, and paleoproductivity as well as origin and accumulation of OM of the Lucaogou sediments.It is suggested that no recycling sediments in all the studied samples, based on parameters including the Th/Sc vs. Zr/Sc plot, the Chemical Index of Alteration (CIA) being linearly dependent on Weathering Index of Parker (WIP), and the high Index of Compositional Variability. The provenance mainly from intermediate-felsic volcanic rocks (e.g., granodiorite, andesite and dacite) is supported by the bivariate plots of Euanom vs. Th/Sc, La/Th vs. Hf, La/Sc vs. Co/Th, Cr/Th vs. Sc/Th, Y/Ni vs. Cr/V, and Nb/Y vs. Zr/TiO2 as well as triangular diagrams of mafic–felsic–weathering, M+–4Si–R2+ and Rb/V–Zr/Zn–Sc/Nb. The continental island arc is inferred from paleotectonic setting discrimination diagrams (i.e., the La–Th–Sc, Th–Co–Zr/10 and Th–Sc–Zr/10 ternary as well as Ti/Zr vs. La/Sc binary diagrams). The chemical weathering indices (i.e., the CIA, WIP, weathering index (W), Weathering Intensity Scale, Sodium Depletion Index, and Ga/Rb vs. K2O/Al2O3 binary diagram) indicate the paleoclimate conditions were cold/arid with weak chemical weathering in a warming and/or enhanced continental weathering episode. Besides, the Sr/Ba ratios and gallium concentrations indicate the paleosalinity was brackish to hypersaline and was higher in the lower member in relation to that in the upper member. However, the suboxic environment of the benthic water (inferred from the MoEF vs. UEF co-variations and Corg/P ratios as well as large sizes of framboidal pyrites) and the moderate paleoproductivity (evaluated via the Sibio, Babio, and Pbio values, as well as Ni/Al and Cu/Al ratios) caused by predominate algae and bacteria (inferred from the organic petrography) kept stable in the paleolake during this period. The OM accumulation was mainly controlled by the preservation conditions rather than the paleoproductivity and limited detrital inputs/low deposition rates, which was indicated by the plot of Co × Mn values vs. Cd/Mo ratios and the total organic carbon contents being negatively related to stable carbon isotope compositions of OM.

The Evolution of the Magnetic Properties of Iron Borate Single Crystals Doped with Gallium

Highly perfect FeBO3 and Fe0.91Ga0.09BO3 single crystals were studied in a wide temperature range using SQUID magnetometry. A theoretical model describing the temperature and field dependences of the magnetization of single crystals has been developed. It is found that even a small concentration of gallium,which is a diamagnetic impurity, substantially affects the magnetic properties of single FeBO3 crystals. In par-ticular, the Fe0.91Ga0.09BO3 crystal differs from the pure FeBO3 phase in by a lower magnetic phase transition temperature and a higher antiferromagnetic susceptibility at low temperatures.

Lowering Cost Approach for CIGS-Based Solar Cell Through Optimizing Band Gap Profile and Doping of Stacked Active Layers-SCAPS Modeling.

In this research article, we carry out investigation on compensating the efficiency loss in thin-film CIGS photovoltaic (PV) cell due to absorber coat depth reduction. We demonstrate that the efficiency loss is mainly caused by the disruption of the charge-carrier transport. We propose an architecture engineered with a stepped band gap profile for improving the efficiency of charge-carrier transport and collection. By modifying the gallium content, we tuned the band gap profile of the active layer of a reference experimental cell from which we previously collected all parameters. Using the simulator environment SCAPS-1D, we modeled a three-steps stacking profile of active layer with different gallium contents from one layer to another. Based on the results obtained, the band gap configuration herein proposed appears to be a prospective strategy for high-performance ultrathin Cu(In,Ga)Se2-based PV cell architecture engineering. By combining this approach with the optimization of the active layer doping, we enhanced the yields of the reference structure from 18.93% for a 2 μm active layer to 23.36% for only 0.5 μm thickness of active layer, that is, an enhancement of 4.4%. The fill factor increased from 73.24 to 81.73%, that is, an additional stability indicator value of 8.5%. The good values of the obtained efficiency and the improvement of the fill factor value are relevant indicators of a stable device. Active layer stacking combined with a stepped band gap profile and doping level optimization is definitely providing new perspectives in thin-film CIGS high-performance PV cell achievement.

Discovery of anomalous gallium enriched in stone coal: Significance, provenance and recommendations

Gallium (Ga) is a critical mineral that plays an irreplaceable role in consumer electronics, clean energy technologies and the aerospace industry. Nowadays competition for gallium resources at the national strategic level has begun to emerge, but gallium resources are unevenly distributed globally, and their presence is not guaranteed. New discoveries revealed an average gallium concentration of thirty-one samples from M1, M2, M3 and M4 stone coal-bearing seams of the Cambrian strata on South Qinling Orogenic Belt in central China is 157 mg/kg (9.98–747 mg/kg), which is 27.6-fold higher than the global hard coal average, as well as the existing association of Mo–V–U–Cd–Zn–Ba–Se–Mg–Ni–Cu enrichment. Ga average of these coal seams are 344 mg/kg (M3, 44.5–747 mg/kg, n = 11), 270 mg/kg (M4, 14.3–270 mg/kg, n = 5), 53.8 mg/kg (M2, 22.6–75.4 mg/kg, n = 8) and 19.8 mg/kg (M1, 9.98–34.9 mg/kg, n = 7) respectively, as well as the thickness of approximately 6, 12, 8, and 20 m, which be close to or exceed to the boundary grade standard (30 mg/kg) and minimum recoverable thickness (0.7 m) of gallium resources exploration. These findings indicate that the Cambrian stone coal deposits, especially in the middle and late Cambrian period, should be considered as promising alternative sources of gallium. The anomalous gallium-enriched sediments originated from a complex combination of hydrothermal fluids, original biomass and terrigenous materials. For the M1 stone coal-bearing seams, gallium most likely occurred in the mode of GaAs, GaxIn1-xAs and GaO(OH), while modes of gallium in the M2 to M4 seams is interrelated with the organic affinity and clay minerals. The crude reserve estimate of gallium resources in central China is approximately 10.06 × 104 tons, corresponding to a super-large coal-hosted gallium ore deposit. The unique paleogeographic location and geological structure in central China resulted that this newly discovered deposit is a unique type of gallium-enriched deposit that has been discovered worldwide. These discoveries will provide the critical parameters when developing distinctive beneficiation processes and appropriate extraction procedures, as well as guidance and effective for future prospecting regions of gallium resources around the globe, involving a combination consider the distribution of regional deep–large fault zones and the middle to late Cambrian black rock series deposits.

Gallium-Doped Hydroxyapatite Shows Antibacterial Activity against Pseudomonas aeruginosa without Affecting Cell Metabolic Activity

Calcium phosphates (CaPs) have been used in bone regeneration for decades. Among the described CaPs, synthetic hydroxyapatite (HAp) has a chemical composition similar to that of natural bone. Gallium-containing compounds have been studied since the 1970s for the treatment of autoimmune diseases and have shown beneficial properties, such as antibacterial activity and inhibition of osteoclast activity. In this study, we synthesized hydroxyapatite (HAp) powder with Ga doping ratios up to 6.9 ± 0.5 wt% using the wet chemical precipitation method. The obtained products were characterized using XRD, BET, FTIR, and ICP-MS. Ga3+ ion release was determined in the cell culture media for up to 30 days. Antibacterial activity was assessed against five bacterial species: Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus pyogenes. The biocompatibility of the GaHAp samples was determined in human fibroblasts (hTERT-BJ1) through direct and indirect tests. The structure of the synthesized products was characteristic of HAp, as revealed with XRD and FTIR, although the addition of Ga caused a decrease in the crystallite size. Ga3+ was released from GaHAp paste in a steady manner, with approximately 40% being released within 21 days. GaHAp with the highest gallium contents, 5.5 ± 0.1 wt% and 6.9 ± 0.5 wt%, inhibited the growth of all five bacterial species, with the greatest activity being against Pseudomonas aeruginosa. Biocompatibility assays showed maintained cell viability (~80%) after seven days of indirect exposure to GaHAp. However, when GaHAp with Ga content above 3.3 ± 0.4 wt% was directly applied on the cells, a decrease in metabolic activity was observed on the seventh day. Overall, these results show that GaHAp with Ga content below 3.3 ± 0.4 wt% has attractive antimicrobial properties, without affecting the cell metabolic activity, creating a material that could be used for bone regeneration and prevention of infection.

Manipulate the acidity of gallium doped Silicalite-1 to optimize methanol to propene performance

Optimising the balance between propene selectivity, propene/ethene (P/E) ratio and catalytic stability and unravelling the relationship between the acidity of MFI-zeolites and those performances are challenging goals of great importance in state-of-the-art methanol-to-olefin (MTO) research. We report a strategy to finely control the acidity of MFI-zeolites by incorporating gallium(III) centres into Silicalite-1 (S-1), obtain an optimal GaS-1(1.3) zeolite through optimizing the gallium content by hydrothermal method·NH3-TPD and pyridine-IR reveal that the ratios of Weak/Strong acid sites (W/S ratios) dominates P/E ratios, while the ratios of Lewis/Brönsted acid sites (L/B ratios) determines lifetime of MFI-zeolites during MTP process. The resultant GaS-1(1.3) zeolite exhibits simultaneously remarkable propene selectivity (45.3 %), P/E ratio (14.6) and catalytic stability (>180 h) at full methanol conversion. Compared with HZSM-5 zeolite, the acidity could be weakened by Ga substitution and the optimization of Ga coordination structure creates an optimal acidity for efficient conversion of methanol and thus greatly promotes the application of zeolites in the sustainable manufacturing of light olefins.

Tretiranje boksitnih ostataka - luženje - prvi deo

Introduction/purpose: Bauxite residue as a waste product from the aluminium industry produced through the Bayer process is mainly composed of iron oxide, titanium oxide, silicon oxide and undissolved alumina together with a wide range of other oxides and a minor content of rare earth elements, gallium, vanadium and scandium, which vary according to the country of origin of the bauxite. The extraction of valuable elements from bauxite residues and the minimisation of bauxite residues during different treatments are an open research field. Methods: Different hydrometallurgical and pyrometallurgical methods were used for the treatment of bauxite residues. In this study, the results of the hydrometallurgical treatment of bauxite residue from Alumina Zvornik using sulfuric acid and hydrochloric acid will be shown in order to study the change of the mineralogical composition. Leaching efficiency will be calculated using the ICP OES analysis. The XRD-Analysis was used for the characterization of the initial material and solid residues studying the change of the mineralogical phases. Results: Leaching of bauxite residues with sulphuric and hydrochloric acid leads partially to the change of mineralogical structure and the transfer of elements into a liquid phase. Natural precipitation of iron is observed over time. Silica gel formation is confirmed during leaching of bauxite residues with hydrochloric acid. Conclusion: A new research strategy for treating bauxite residue is needed in order to ensure a complete change of the initial minearlogical structure and the most efficient transfer of metals into a liquid phase.

Are Coal-Hosted Gallium-Rich Ores Elastically Detectable: A Rock-Physics Modeling Perspective

Coal-hosted gallium-rich ores are mainly explored with geochemical analyses, and their elasticities lack research. This paper incorporated core testing, rock-physics modeling, and Monte Carlo simulations to characterize the elastic parameters of gallium-rich cores and discuss whether coal-hosted gallium-rich ores are elastically detectable. The measured cores from No. 6 coal in the Heidaigou mine showed that the gallium contents strongly correlate to the boehmite contents with a 0.96 correlation coefficient. The rock-physics modeling results showed that mineral compositions and contents are critical factors influencing elastic parameters, and elastic parameters in No. 6 coal showed profound heterogeneities as mineral compositions and contents. The preferred parameters for classifying and grouping different mineral-rich cores are the bulk modulus and moduli ratio. Cross-plotting bulk modulus vs. moduli ratio can qualitatively group measured cores and Monte-Carlo simulated realizations into different mineral-rich and saturation states properly. Concerning the factors of boehmite content, porosity, and saturation state, an interpretation template for boehmite-rich coal was proposed and used. As the template interpreted readings close to the measured contents, the built templates can quantitatively interpret boehmite and gallium contents in coal-hosted ores with high precision. In summary, the coal-hosted gallium-rich ores are elastically detectable.

Synthesis and characterization of multi-phase structure, optical and electrical properties on (Ga–Sn) oxide composite thin film by sol-gel method

The structural and optical properties of the films were investigated as a function of increasing high Gallium content amounts in the range 10–30 mol %. The composite thin films were characterized by crystallography, surface morphology, optical and electrical properties. The X-ray diffraction (XRD) method revealed that the composited thin films were multiphase in rutile tetragonal (SnO2) and β phase monoclinic (Ga2O3) type crystal structure with grown strongly in the (200) and (4‾ 01), respectively. In addition, for comparative investigate the effect of high concentration Ga incorporation on the lattice of SnO2 and the mechanism for lattice strain, Williamson-Hall method introduced. The surface morphology was investigated by Field emission Scanning Electron Microscope (FE-SEM) measurement, and it confirmed that crystallite size difference and multi-phase appear with high Ga incorporated. With UV–vis spectrometer, all (Ga–Sn) oxide composite thin films revealed a transparency of approximately 78% in the visible region. For comparative analysis of the band gap of the composite thin film, the estimated value was derived from Tauc plot, and the measured value was investigated by photoluminescence (PL). The electrical sheet resistance was measured by four-point probe method and optimized sheet resistance value of 5.66 kΩ/sq when the mixture of Ga 20 mol % concentration.

Optical Properties Evaluation of CuIn1-xGaxSe2 Thin Films Using OPAL2 Calculator

OPAL2 calculator has proved to be an effective technique for simulating optical losses in various materials for various applications. This study demonstrates the use of this softwareto simulate the transmittance (T) and reflectance (R) and hence evaluate the optical properties of flash evaporated CuIn1-xGaxSe2(CIGS) thin films with a ratio x = 0.28 deposited on stainless-steel (STS) and glass substrates. The simulation results exhibit excellent accuracy of the modeled design presented in this work. The CIGS with a ratio of gallium x = 0.3 showed the best matching between simulated and experimental T and R patterns. Moreover, the simulation shows that an increase in the gallium concentration increases optical losses. Finally, the results demonstrate the application of the freeware program OPAL2 to practically simulate the optical proprieties of CIGS thin films.

Effect of residual chlorine on fluorescence emission of Dy3+ doped chalcogenide glasses with low gallium content

AbstractChlorine or chlorides are usually used as a dehydrating agent for removing the O‐H or S(Se)‐H in the preparation of high‐purity chalcogenide glasses. However, the residual chlorine in some rare‐earth ions doped chalcogenide glasses was found to have a great negative impact on fluorescence emission. In this work, the effect of residual chlorine on the fluorescence emission of Dy3+ ions in serial (Ge)GaAsSbS glasses was studied quantitatively, and the reasons were discussed. Cl2 gas and SbCl3 were used as the source of chlorine and their residual contents were controlled by the post‐distillation process and added content, respectively. The results can give some suggestions for how to eliminate the negative effects of chlorine and improve the glass’ optical gain properties.

The Fabrication of Indium–Gallium–Zinc Oxide Sputtering Targets with Various Gallium Contents and Their Applications to Top-Gate Thin-Film Transistors

We prepared amorphous indium–gallium–zinc oxide (a-IGZO) thin films with various Ga content ratios and investigated their feasibility as the active channel layers of top-gate thin-film transistors (TFT). First, the 2-inch IGZO sputtering targets with stoichiometric ratios of InGaZn2O5, InGaZnO4, and InGa2ZnO5.5 were fabricated using In2O3, Ga2O3, and ZnO oxide powders as raw materials via sintering treatments at temperatures ranging from 900 °C to 1300 °C for 6 h or 8 h. X-ray diffraction analysis indicated that the InGaZn2O5 and InGaZnO4 targets are single-phase structures whereas the InGa2ZnO5.5 target is a two-phase structure. Hall effect measurement indicated that the a-InGaZn2O5 and a-InGaZnO4 layers possess a carrier concentration (N) of about 1019 cm−3 and a resistivity (ρ) of about 10−2 Ω·cm; however, the N of the a-InGa2ZnO5.5 layer is only 1017 cm−3, and the ρ is about 1 to 4 Ω·cm. Moreover, the a-InGaZn2O5 layer exhibited the highest Hall-effect mobility (μHall) of 21.17 cm2·V−1·sec−1. This indicated that the impedance of Ga3+ ions to carrier migration is the main factor affecting the electrical properties of a-IGZO layers. Ga content in the a-IGZO channel similarly affects the performance of the TFT devices prepared in this study. The annealing at 300 °C for 1 h in an ambient atmosphere was found to significantly improve the electrical properties of the TFT devices. The best performance was observed in the a-InGaZnO4 TFT sample subjected to post-annealing at 300 °C with Vth = −0.85 V, μFE = 8.46 cm2, V−1·sec−1, SS = 2.31, V·decade−1, and Ion/Ioff = 2.9 × 104.

Preparation and Study of Cadmium Oxide Doped Gallium Oxide Thin Films and application of Gas Sensor

In this paper, the structure and optical properties of pure cadmium oxide films, and doped with gallium oxide have been achieved, the films were deposited on glass and silicon substrates, with different ratios (1,3,5,7)% via spry pyrolysis method, at the substrate temperature of ̊ C300. XRD results showed that all prepared films had a cubic polycrystalline structure, with preferred orientation of (111) for cadmium oxide. Surface morphology was studied using atomic force microscope (AFM), the grain size of the thin films was about 105.42-69.07 nm, with surface roughness is about (3.32-0.901) nm and root mean square (RMS) (3.97-1.05) nm for cadmium oxide films. The optical properties were studied using UV-VIS spectroscopy at wavelength (300-1100 nm), It was observed that the value of transmittance increases when the gallium doping are increasing and the films have a direct energy gap about (2.3-4) eV that increases with the increase in gallium concentration. Sensitivity properties of pure cadmium oxide films, and doped with gallium oxide was deposed on silicon substrates of NO2 gas at different operation temperatures was found that the films of CdO doped with Gallium oxide on silicon substrate has greater sensitivity than the films than the undoped and that the doping has improved the sensitivity of the membranes CdO.

Analysis of coal ash samples from thermal power plants of India for their gallium content using NAA and EDXRF techniques

Coal fly ash (CFA) is an important secondary source for the recovery of gallium (Ga) which has a high potential for its wide applications in many strategic fields such as cellular communications and direct broadcast satellite.Various coal fly and bottom ash samples obtained from thermal power plants located in different parts of India were investigated for their gallium content using NAA and EDXRF techniques. The concentration of gallium in NIST SRM 1633b CFA is not available in NIST certificate and hence was established using k0 based IM-NAA method along with the other certified elements like As, Ce, Co, Eu, Fe, K etc. In addition, the gallium concentration in the NIST SRM was also obtained by relative NAA using Ga2O3 as a standard towards the validation of IM-NAA. Using the NIST SRM, the gallium content in the ash samples of Bituminous coal collected from South Central and Eastern India was found to be from 17.2 to 47.9 mg/kg whereas the same was 6.3–33.3 mg/kg for the ash samples of Lignite coal collected from the South-Central India and Western India. The gallium concentrations obtained by NAA in coal ash samples were compared with another non-destructive assay technique, i.e. EDXRF and the results are found to be in good agreement. These samples were proved to be a potential secondary source of gallium, available in India.

Quantification of Aluminum Gallium Arsenide (AlGaAs) Wafer Plasma Using Calibration-Free Laser-Induced Breakdown Spectroscopy (CF-LIBS).

In this work, we report the results of the compositional analysis of an aluminum gallium arsenide (AlGaAs) sample using the calibration-free laser-induced breakdown spectroscopy (CF-LIBS) technique. The AlGaAs sample was doped with three various concentrations of gallium (Ga), arsenic (As), and aluminum (Al), as reported by the manufacturer, and the CF-LIBS technique was employed to identify the doping concentration. A pulsed Q-switched Nd: YAG laser capable of delivering 200 and 400 mJ energy at 532 and 1064 nm, respectively, was focused on the target sample for ablation, and the resulting emission spectra were captured using a LIBS 2000+ spectrometer covering the spectral range from 200 to 720 nm. The emission spectra of the AlGaAs sample yielded spectral lines of Ga, As, and Al. These lines were further used to calculate the plasma parameters, including electron temperature and electron number density. The Boltzmann plot method was used to calculate the electron temperature, and the average electron temperature was found to be 5744 ± 500 K. Furthermore, the electron number density was calculated from the Stark-broadened line profile method, and the average number density was calculated to be 6.5 × 1017 cm−3. It is further observed that the plasma parameters including electron temperature and electron number density have an increasing trend with laser irradiance and a decreasing trend along the plume length up to 2 mm. Finally, the elemental concentrations in terms of weight percentage using the CF-LIBS method were calculated to be Ga: 94%, Al: 4.77% and As: 1.23% for sample-1; Ga: 95.63%, Al: 1.15% and As: 3.22% for sample-2; and Ga: 97.32%, Al: 0.69% and As: 1.99% for sample-3. The certified concentrations were Ga: 95%, Al: 3% and As: 2% for sample-1; Ga: 96.05%, Al: 1% and As: 2.95% for sample-2; and Ga: 97.32%, Al: 0.69% and As: 1.99% for sample-3. The concentrations measured by CF-LIBS showed good agreement with the certified values reported by the manufacturer. These findings suggest that the CF-LIBS technique opens up an avenue for the industrial application of LIBS, where quantitative/qualitative analysis of the material is highly desirable.