Ratio Of Gallium Research Articles

Confronting solutions of the Gallium Anomaly with reactor rate data

Recently, several models have been suggested to reduce the tension between Gallium and reactor antineutrino spectral ratio data which is found in the framework of 3+1 active-sterile neutrino mixing. Among these models, we consider the extensions of 3+1 mixing with a finite wavepacket size, or the decay of the heaviest neutrino ν4, or the possibility to have a broad ν4 mass distribution. We consider the reactor antineutrino rate data and we show that these models cannot eliminate the tension between Gallium and reactor rate data that is found in the 3+1 neutrino mixing framework. Indeed, we show that the parameter goodness of fit remains small. We consider also a model which explains the Gallium Anomaly with non-standard decoherence in the framework of three-neutrino mixing. We find that it is compatible with the reactor rate data.

P‐154: Late‐News Poster: High‐Performance Indium‐Gallium Oxide Thin‐Film‐Transistors via Plasma‐Enhanced Atomic‐Layer‐Deposition

We report the fabrication of high‐performance indium‐gallium oxide (IGO) thin‐film transistors (TFTs) via plasma‐enhanced atomic‐layer‐deposition (PE‐ALD) process with cation composition ratio variation. With accurate control of the composition ratio, IGO(12:3) TFTs showed stable characteristics along with high field‐effect mobility (μFET) of 70.69 cm 2 /Vs. Furthermore by increasing the gallium ratio, IGO(6:3) TFTs showed extremely stable characteristics with threshold voltage (VTH) variations lower than 0.1 V in both positive bias stress (PBS) and negative bias stress (NBS) conditions.

Effects of Indium and Gallium ratio on tarnish resistance, corrosion and mechanical properties of 950 silver alloy

The effects of Indium (In) and Gallium (Ga) ratio on tarnish resistance, corrosion and mechanical properties of 950 silver alloy were studied. 950 Silver alloy with aluminium (Al), silica (Si) and germanium (Ge) were added with In and Ga at the range of 0.44 to 1.90 weight percent. The increment of secondary structure with Ge-Si rich phase in Ag-Al alloy increases hardness, but reduces ultimate tensile strength. The addition of In and Ga improves tarnish and corrosion resistance. The color differences as indicated by Delta E tolerances (DE*) of Ag-Al alloys are in the range of 8.64 to 11.40 while this property of Ag-Cu is 39.37. Ecorr of Ag-Al alloys are in the range of -0.068 to -0.010 V which are higher than that of Ag-Cu Alloy (-0.147 V). Besides, Ga is more effective for tarnish and corrosion resistance than In. However, Ga/In co-addition reduces these properties by the formation of Ge-Si-Ga-In phase. The protective thin film of Ag-Al alloy was detected by XPS. The Al2O3, In2O3 and Ga2O3 films were found. When the proportion of Ga in Ag-Al alloys increases, the hardness marginally increases while the tensile strength slightly reduces. The additions of Al, Ga, In, Ge and Si reduce the melting point of Ag-Al alloys comparing with Ag-Cu alloy and simultaneously improve the casting quality.

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.

Modelling and investigation of the electrical properties of CIGS/n-Si heterojunction solar cells

Ag/CIGS/n-Si/Al solar cells which were formed basing ultrathin film thickness by Pulse Laser Deposition (PLD) method, to be used as a sub-solar cell in tandem solar cells. The thickness of CIGS-ultrathin films enhancement with increasing the laser ablation pulse number. Crystallinity of CIGS-ultrathin films have improved and CIGS-ultrathin films have more photon absorption. Indium and Gallium ratios decreased and Copper and Selenium ratios increased in CIGS-ultrathin film as laser pulse number increased. The band gap, dielectric constant, Urbach energy and refractive index of CIGS ultrathin films were calculated. The rectification rate and photo current of CIGS/n-Si hetero-junctions were calculated based on CIGS-ultrathin film thickness under the illumination. Using SCAPS-1D program, the efficiencies of CIGS/n-Si heterojunction solar cells were calculated depend Auger electron/hole recombination coefficient, the interface defect density and the hole carrier density. Also, Jsc, FF, Voc, and efficiencies of CIGS solar cells were calculated based on contact surface recombination velocity and operation temperature. To room temperature, the calculated PV parameters were founded to be very compatible by the experimental parameters. CIGS-ultrathin film thicknesses indicating the highest efficiencies have been determined.

(Digital Presentation) Investigation of Top Electrodes Impact on Performance of Transparent Amorphous Indium Gallium Zinc Oxide (a-InGaZnO) Based Resistive Random Access Memory

The traditional von Neumann architecture limits the increase in computing efficiency and results in massive power consumption in modern computers due to the separation of storage and processing units. The novel neuromorphic computation system, an in-memory computing architecture with low power consumption, is aimed to break the bottleneck and meet the needs of the next generation of artificial intelligence (AI) systems. Thus, it is urgent to find a memory technology to implement the neuromorphic computing nanosystem. Nowadays, the silicon-based flash memory dominates non-volatile memory market, however, it is facing challenging issues to achieve the requirements of future data storage device development due to the drawbacks, such as scaling issue, relatively slow operation speed, and high voltage for program/erase operations. The emerging resistive random-access memory (RRAM) has prompted extensive research as its simple two-terminal structure, including top electrode (TE) layer, bottom electrode (BE) layer, and an intermediate resistive switching (RS) layer. It can utilize a temporary and reversible dielectric breakdown to cause the RS phenomenon between the high resistance state (HRS) and the low resistance state (LRS). RRAM is expected to outperform conventional memory device with the advantages, notably its low-voltage operation, short programming time, great cyclic stability, and good scalability. Among the materials for RS layer, indium gallium zinc oxide (IGZO) has shown attractive prospects in abundance and high atomic diffusion property of oxygen atoms, transparency. Additionally, its electrical properties can be easily modulated by controlling the stoichiometric ratio of indium and gallium as well as oxygen potential in the sputter gas. Moreover, since the IGZO can be applied to both the thin-film transistor (TFT) channel and RS layer, it has a great potential for fully integrated transparent electronics application.In this work, we proposed amorphous transparent IGZO-based RRAMs and investigated switching behaviors of the memory cells prepared with different top electrodes. First, ITO was choosing to serve as both TE and BE to achieve high transmittance. A multi-target magnetron sputtering system was employed to deposit all three layers (TE, RS, BE layers) on glass substrate. I-V characteristics were evaluated by a semiconductor parameter analyzer, and the bipolar RS feature of our RRAM devices was demonstrated by typical butterfly curves. The optical transmission analysis was carried out via a UV-Vis spectrometer and the average transmittance was around 80% out of entire devices in the visible-light wavelength range, implying high transparency. We adjusted the oxygen partial pressure during the sputtering of IGZO to optimize the property because the oxygen vacancy concentration governs the RS performance. Electrode selection is crucial and can impact the performance of the whole device. Thus, Cu TE was chosen for our second type of device because the diffusion of Cu ions can be beneficial for the formation of the conductive filament (CF). A ~5 nm SiO2 barrier layer was employed between TE and RS layers to confine the diffusion of Cu into the RS layer. At the same time, this SiO2 inserting layer can provide an additional interfacial series resistance in the device to lower the off current, consequently, improve the on/off ratio and whole performance. Finally, an oxygen affinity metal Ti was selected as the TE for our third type of device because the concentration of the oxygen atoms can be shifted towards the Ti electrode, which provides an oxygengettering activity near the Ti metal. This process may in turn lead to the formation of a sub-stoichiometric region in the neighboring oxide that is believed to be the origin of better performance.In conclusion, the transparent amorphous IGZO-based RRAMs were established. To tune the property of RS layer, the sputtering conditions of RS were varied. To investigate the influence of TE selections on switching performance of RRAMs, we integrated a set of TE materials, and a barrier layer on IGZO-based RRAM and compared the switch characteristics. Our encouraging results clearly demonstrate that IGZO is a promising material in RRAM applications and breaking the bottleneck of current memory technologies.

The Effectiveness of Ga Percent on the Electrical Characteristics of Al/CuIn1-xGaxSe2/ITO Schottky Junctions

The electrodeposition method has been employed to deposit our quaternary semiconductor thin films CuIn1-xGaxSe2 (CIGS) which is deposited on Indium Tin Oxide (ITO) substrates with different Gallium ratios (x=0, 0.2, 0.4, 0.6, 0.8 and 1). The structural and optical characteristics variation of the films with altering Ga percent has been studied. The impact of changing the Ga/(In+Ga) atomic ratio on the electrical transport characteristics of electrodeposited CIGS thin films has been investigated using I-V and C-V measurements. All junctions have revealed the Schottky behavior. The energy gap of the studied compositions has increased with increasing Ga content. This lowered the values of charge mobility in the investigated films. Besides, the optimum Ga/(In+Ga) atomic proportion in the view of the obtained results is achieved by adding Ga with 20 %. Also, this finding approves the validation of our proposed criterion in expecting the most efficient photovoltaic junctions. The obtained results could improve our current knowledge of the quaternary photovoltaic solar cells.

Performance analysis of CuInSe2 based solar cells using SCAPS-1D

In this study we have simulated a CuInSe2 based solar cell. CuInSe2 solar cells belongs to the second generation of PV technology.The conventional structure of the cell Al/ZnO:Al/ZnO/CdS/CuInSe2/Mo have been studied through. The simulation was performed by SCAPS-1D, one dimensional solar cell capacitance simulator, which is created by Marc Burglman from university of Gent in Belgium. Several effects like thickness, carrier density of CuInSe2 and gallium ratio were studied. The results of simulation showed that we have to control the thickness of absorber layer because going beyond 2 µm of thickness affect the performance of the cell especially fill factor that decreases even if the power conversion efficiency increases. The variation of carrier density showed that the optimum value is in the range of 1016 cm−3. This value should also be controlled to not have a degenerate compound. As for gallium content results showed that under a ratio of 0.33 we achieved an efficiency of 13.31%, which is due to the amelioration of absorption. Another effect has been evaluated is the effect of temperature, we varied temperature from 300°K to 400°K in order to see its influence. The results of varying temperature showed that all parameters decrease except the density of short circuit that increased. This study has helped us to understand the performance of CuInSe2 solar cell by knowing parameters that need to be controlled during production process.

Study on decomposition kinetics of activated alunite concentrate from copper tailings and leaching behavior of valuable elements

Alunite flotation concentrate extracted from copper tailings is considered to be a resource for recovery of potassium, aluminum and gallium, which mainly contains alunite, quartz, dickite and pyrite phases by the X-ray diffraction analysis. The calcination temperature and time affect not only the decomposition ratio of alunite but also the phase change of alumina. The effects of mechanical activation on thermal decomposition and leaching behavior of the alunite concentrate are investigated. The decomposition reactions of pyrite and alunite happen at 400–500 °C and 500–800 °C respectively, and the decomposition of alunite involves two stages, dehydration and desulphation. The mechanical activation produces some amorphisation and structural disordering, which is responsible for the decrease of apparent activation energy of dehydration as well as desulphation. The leaching ratio of potassium, aluminum and gallium increases with activation time.

The role of coherent epitaxy in forming a two-dimensional electron gas at LaIn1-xGaxO3/BaSnO3 interfaces

Some oxide interfaces are known to exhibit unique properties such as a 2D electron gas, controlled by epitaxial strain and coherency between the two layers. Here, we study variation in the 2D electron density in the polar LaIn1-xGaxO3/Ba0.997La0.003SnO3 interface with changing x and LaIn1-xGaxO3 layer thickness. We find that the 2D electron density decreases as the gallium alloying ratio increases and the interface conductance eventually disappears, which shows that an interface with polar discontinuity is not a sufficient condition for 2D electron gas formation. The interface conductance reaches its maximum value when the LaIn1-xGaxO3 layer thickness is approximately 20 Å, beyond which conductance decreased to a constant value. Atomistic imaging reveals that dislocations start to form as the gallium ratio increases, forming away from the interface and then moving closer with increasing gallium alloying. The dislocations eventually destroy coherency in the case of LaGaO3 and suppress the formation of a 2D electron gas.

Development of \u03b2-Ga2O3 layers growth on sapphire substrates employing modeling of precursors ratio in halide vapor phase epitaxy reactor

Gallium oxide is a promising semiconductor with great potential for efficient power electronics due to its ultra-wide band gap and high breakdown electric field. Optimization of halide vapor phase epitaxy growth of heteroepitaxial upbeta-Ga2O3 layers is demonstrated using a simulation model to predict the distribution of the ratio of gallium to oxygen precursors inside the reactor chamber. The best structural quality is obtained for layers grown at 825–850 °C and with a III/VI precursor ratio of 0.2. Although the structural and optical properties are similar, the surface morphology is more deteriorated for the upbeta-Ga2O3 layers grown on 5 degree off-axis sapphire substrates compared to on-axis samples even for optimized process parameters. Cathodoluminescence with a peak at 3.3 eV is typical for unintentionally doped n-type upbeta-Ga2O3 and shows the appearance of additional emissions in blue and green region at ~ 3.0, ~ 2.8, ~ 2.6 and ~ 2.4 eV, especially when the growth temperatures is lowered to 800–825 °C. Estimation of the band gap energy to ~ 4.65 eV from absorption indicates a high density of vacancy defects.

Design of porous Ga doped TiO2 nanostructure for enhanced solar light photocatalytic applications

Green and porous Ga3+ doped TiO2 nanostructures have been successfully prepared using plant waste extract and ultrasonic irradiation. The produced nanomaterials have been investigated using XRD, Raman, FTIR, SEM, TEM, BET and XPS. The results revealed the formation of micro-/macro-porous TiO2 anatase with high surface area compared to pure TiO2 prepared under identical conditions. All results revealed the successful incorporation of Ga3+ ions in the TiO2 crystal at all gallium ratio while XPS results showed the formation of Ga2O3 at high gallium concentration (5 and 10 wt. %). The effect of Ga doping was found to greatly enhance the photocatalytic activity of TiO2 for MB and phenol degradation with best result obtained for 0.5 wt. % of Ga.

A Novel Strategy for Preparing Stretchable and Reliable Biphasic Liquid Metal

AbstractLow‐melting liquid metal is a hugely promising material for flexible conductive patterns due to its excellent conductivity and supercompliance, especially low‐cost and environmental liquid processing technology. However, the ever‐present fluidity characteristic greatly limits the stable shape and reliability of prepared liquid metal conductive electronics. Herein, a novel solidification strategy of liquid GaIn alloys by Ni doping and heat treatment is first reported, which can efficiently create a solid phase in the liquid metal and provide an effective solution for practical applications. Particularly, the liquid characteristic is preserved for conveniently fabricating different flexible electronic circuits, and then the solidification is carried out on prepared conductive patterns by heat treatment. The solidification mechanism is revealed by the interface chemical reaction between Ni and GaIn, creating the solid phase of intermetallic compound (Ga4Ni3 and InNi3) during heat treatment. Moreover, a biphasic GaInNi can be obtained by regulating the atomic ratio of gallium, indium, and nickel. As a result, the obtained GaInNi possesses extremely low sheet resistance (15 ± 4.5 to 135 ± 2.5 mΩ sq−1) and the variation of ΔR/R0 exhibits low level (0–2) when strained up to 100%, which offers a promising strategy to prepare stretchable and reliable liquid metal electronics.

Нелегированный высокоомный буферный слой GaN для HEMT AlGaN/GaN

In this paper the possibility of obtaining the intentionally undoped high resistance GaN buffer layers in AlGaN/GaN heterostructures with high electron mobility for transistors by ammonia molecular beam epitaxy was demonstrated. The growth conditions based on background impurity concentrations and point defects calculations for different gallium and ammonia flows ratios were optimized.

Combustion synthesis and photoelectrochemical characterization of gallium zinc oxynitrides

Abstract

Elevated-temperature etching of gallium nitride (GaN) in dual-frequency capacitively coupled plasma of CH4/H2 at 300–500 °C

Elevated-temperature etching with CH4/H2 plasma chemistry at 300 °C improves damage-less optical properties of GaN, solving issues of degradation on near-band-edge photoluminescence intensity on plasma etching at lower temperatures than 300 °C. Damage-less etching properties in a smooth surface, high photoluminescence intensity, and substantial stoichiometric ratio of gallium and nitrogen were obtained when the CH4/H2 chemistry with substrate temperatures at 300–500 °C.

Combustion Synthesis and Photoelectrochemical Characterization of Metal Oxynitrides Using GaxZn1-XOyN1-Y as a Model Candidate

Utilization of solar energy is a necessary path forward to deal with the looming energy crisis and worldwide effects of fossil fuel usage. A key component of this utilization is how to store excess solar energy for use on demand. One such method is splitting water into hydrogen and oxygen, both of which can be stored and either burned as fuel or used as feedstock components in industrial processes to synthesize high-value materials. Metal oxynitrides have shown great potential as photocatalysts for overall water splitting applications. Incorporation of nitrogen into metal oxides narrows the band gap to enable absorption of light in the visible spectrum. The typical synthesis of a metal oxynitride, however, requires annealing temperatures at or above 1000 oC and nitridation by flowing pure ammonia gas for anywhere from 1 to 48 hours. Such harsh synthesis conditions can limit the discovery of new candidate materials. In our work, we have prepared an array of gallium zinc oxynitrides (GaxZn1-xOyN1-y) as a model system using a combustion synthesis method and demonstrate that gallium zinc oxynitrides can be synthesized in 30 minutes at 500 oC using this method. X-ray diffraction (XRD), UV-visible spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) are used to characterize the physical properties of the as-synthesized materials. XPS analysis reveals that as much as 50% nitrogen substitution in the metal oxide lattice can be achieved, dependent on the ratio of gallium and zinc nitrates used as precursors. XPS also reveals that the nitrogen valency is that of a nitride material, as would be expected for a substitution into the crystal lattice. Relative atomic concentrations from XPS also reveals that the complex formed is essentially GaN:ZnO. UV-visible spectroscopy reveals that the band gap of the GaxZn1-xOyN1-ymaterials can be controlled simply by altering the precursor ratio. X-ray diffraction measurements reveal shifts in the crystalline peaks from ZnO toward GaN, confirming the incorporation of nitrogen into the lattice. The as-synthesized products are capable of generating photocurrent from visible light irradiation and are able to carry out water splitting in pure water without any co-catalysts, such as Pt, IrO2, or Rh/Cr2O3. Finally, we discuss how to take the results gained from this work and expound upon it to begin the search for new candidate oxynitride materials, including potential high-throughput methods for rapid screening of such candidates. We also discuss the apparent conditions necessary for successful formation of an oxynitride material based on initial experiments with new candidates. Figure caption: Picture of as-synthesized powders from an initial Ga:Zn:urea molar ratio of (A) 1:1:0 and (B) 1:1:10. Figure 1

Surface treatment for Schottky barrier photodetector based on Au/GaZnO nanorods/Au structure

In this paper, we will report the geometrical morphology, optical properties, electrical properties of the gallium doped ZnO nanorods (GZO NRs), as well as the performance of Au/GZO NRs/Au structure photodetector. We found that with the increase of the molar ratio of gallium, the length of the nanorods becomes smaller and the radial width increases, and the shape is more toward the hexagonal prism, and the grain radius increases. Also with the increase of the doping ratio, the optical absorption edge had a blueshift phenomenon, and the conductivity is enhanced. Moreover, in order to obtain the high performance of the photodetector, GZO NRs were treated by hydrogen peroxide and ohmic contact Au/GaZnO Nanorods/Au device was changed to a Schottky contact device, which showed a smaller dark current and faster response speed compared with ohmic contact device.

Effect of the chemical composition of Cu–In–Ga–Se layers on the photoconductivity and conversion efficiency of CdS/CIGSe solar cells

The effect of the [Ga]/[In+Ga] ratio of gallium and indium on the microwave photoconductivity of Cu–In–Ga–Se (CIGSe) films and on the efficiency of solar cells fabricated in accordance with the same technology is investigated. According to the observations of a field-emission scanning electron microscopy (FESEM), the grain size decreases with increasing Ga content. With increasing gallium content in the samples, the photogenerated-electron lifetime and the activation energy of the microwave photoconductivity also decrease. The changes in the activation energy of the through conduction in darkness are less than 20%. Analysis of the obtained data shows that the known effect of the gallium gradient on the efficiency should be associated with modification of the internal structure of grains instead of with their boundaries.

Quasi Fermi level splitting of Cu-rich and Cu-poor Cu(In,Ga)Se2 absorber layers

The quasi Fermi level splitting is measured for Cu(In,Ga)Se2 absorber layers with different copper to (indium + gallium) ratios and for different gallium contents in the range of 20%–40%. For absorbers with a [Cu]/[In + Ga] ratio below one, the measured quasi Fermi level splitting is 120 meV higher compared to absorbers grown under copper excess independent of the gallium content, contrary to the ternary CuInSe2 where the splitting is slightly higher for absorber layers grown under copper excess. Possible explanations are the gallium gradient determined by the secondary ion mass spectrometry measurement which is less pronounced towards the surface for stoichiometric absorber layers or a fundamentally different recombination mechanism in the presence of gallium. Comparing the quasi Fermi level splitting of an absorber to the open circuit voltage of the corresponding solar cell, the difference for copper poor cells is much lower (60 meV) than that for copper rich cells (140 meV). The higher loss in V OC in the case of the Cu-rich material is attributed to tunneling enhanced recombination due to higher band bending within the space charge region.