Properties Of Gallium Research Articles

Gallium‐Based Liquid Metal Composites and the Continuous Forming Methods

Due to the dual nature of metal and fluid, gallium‐based liquid metals with a low melting point at or around room temperature have gained growing interest recently. Although more properties of gallium are developed, their intrinsic properties are not able to meet the increasing requirement from the scientific and industrial community. To broaden its applications, many kinds of gallium‐based liquid metal composites are prepared and applied in the cutting‐edge fields like biomedical engineering, flexible robots, heat management, and so on. To summarize the latest progress and promote development, this review summarizes the recent progress of liquid metal composites and the continuous forming methods recently, including the physical and chemical properties of gallium‐based liquid metal, composites prepared through physical doping and surface modification, and the continuous forming approaches. Further outlook including expectations and challenges of gallium‐based liquid metal composites is also presented.

Collagen Hydrolysate Effects on Photodynamic Efficiency of Gallium (III) Phthalocyanine on Pigmented Melanoma Cells.

The conjugation of photosensitizer with collagen seems to be a very promising approach for innovative topical photodynamic therapy (PDT). The study aims to evaluate the effects of bovine collagen hydrolysate (Clg) on the properties of gallium (III) phthalocyanine (GaPc) on pigmented melanoma. The interaction of GaPc with Clg to form a conjugate (GaPc-Clg) showed a reduction of the intensive absorption Q-band (681 nm) with a blue shift of the maximum (678 nm) and a loss of shape of the UV-band (354 nm). The fluorescence of GaPc, with a strong emission peak at 694 nm was blue shifted due to the conjugation which lower intensity owing to reduce quantum yield (0.012 vs. 0.23, GaPc). The photo- and dark cytotoxicity of GaPc, Glg and GaPc-Clg on pigmented melanoma cells (SH-4) and two normal cell lines (BJ and HaCaT) showed a slight decrease of cytotoxicity for a conjugate, with low selectivity index (0.71 vs. 1.49 for GaPc). The present study suggests that the ability of collagen hydrolysate to form gels minimizes the high dark toxicity of GaPc. Collagen used for conjugation of a photosensitizer might be an essential step in advanced topical PDT.

Оптические свойства квазиобъемных кристаллов нитрида галлия со структурой высокоориентированной текстуры

The results of a study of the optical properties of gallium nitride samples with a highly oriented texture structure grown without the use of traditional semiconductor or sapphire substrates are presented. It is shown that the stacking faults contained in the GaN blocks of the texture of the studied material are self-organized heteropolytype nanostructures, and that the effective luminescence in the ultraviolet spectral region associated with stacking faults I1 in the basal plane is determined by optical transitions of excitons localized near such natural defects in the single-crystalline bulk of the blocks of the GaN texture.

The Effect of RF Power on the Properties of Gallium and Aluminium Co-doped Zinc Oxide (GAZO) Thin Films

X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and spectrophotometry were used to study the effect of RF power on the properties of gallium and aluminium co-doped zinc oxide (GAZO) thin films for optoelectronic device fabrication. Two peaks appeared in the XPS spectra of the Zn 2p core-level at 1045 and 1022 eV, and these were assigned to $${\text{Zn}}~2{{\text{p}}_{1/2}}$$ and $${\text{Zn}}~2{{\text{p}}_{3/2}}$$ , respectively. The O 1s core-level revealed peaks at 530 and 531 eV which indicated the presence of two different forms of oxygen. Raman spectroscopy confirmed the films’ hexagonal wurtzite crystal structure and revealed the presence of few defects and negligible residual tensile stress. Spectral dependence of the refractive index was analyzed on the basis of the Cauchy’s dispersion model and the Wemple and DiDomenico (WDD) single oscillator model. Low refractive indices (1.6–2.0) and nearly zero extinction coefficients were obtained in the visible region (400–700 nm), indicating the high transparency nature of the GAZO thin films. The optical band gap decreased with increasing RF power, in accordance with the Burstein–Moss effect. Low Urbach energy values were obtained at low RF power, indicating less structural disorder. The free carrier concentration to effective mass ratio $$({N_c}{\text{/}}{m^*})$$ , plasma frequency $$({\omega _P})$$ and zero frequency dielectric constant $$({\varepsilon _\infty })$$ were determined. Films deposited at 150 W exhibited the optimum optical properties, desirable for optoelectronic application.

Microstructure and optoelectronic properties of gallium–magnesium codoped zinc oxide thin films by magnetron sputtering technique

The gallium–magnesium codoped zinc oxide (GMZO) thin films were deposited on glass substrates by radio frequency magnetron sputtering technique in an argon atmosphere. The influence of substrate temperature on the microstructure, morphology and optoelectronic properties of thin films was investigated by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, four-point probe and spectrophotometry. It is found that all the deposited films have a hexagonal structure and a preferred orientation along the c-axis perpendicular to the substrate. As the substrate temperature increases, the dislocation density, lattice strain and electrical resistivity decrease initially and then increase, while the average crystallite size, average visible transmittance and figure of merit exhibit the reverse variation trend. The GMZO thin film deposited at the substrate temperature of 570 K possesses the best optoelectronic properties, with the largest average crystallite size of 52.05 nm, the lowest dislocation density of 3.69 × 1014 lines m− 2, the minimum lattice strain of 1.10 × 10− 3, the lowest electrical resistivity of 1.62 × 10− 3 Ω cm, the highest average visible transmittance of 88.63% and the maximum figure of merit of 5.11 × 103 Ω−1 cm− 1. The optical energy gaps of the films were evaluated by extrapolation method and observed to be in the range of 3.34–3.55 eV. Furthermore, the complex refractive index, the complex dielectric constant and the dissipation factor were determined by optical characterization methods, and the dispersion behaviour of refractive index was studied in terms of the single electronic oscillator model. The results show that the microstructure and optoelectronic properties of the GMZO thin films are dependent on substrate temperature.

Molecular Oxygen Adsorbed on Gallium Doped Graphene: A First-Principles Study

The adsorption of molecular oxygen on gallium doped graphene sheet is investigated using first-principles density functional theory calculations. The adsorption energy of O2 on gallium doped graphene is calculated after determining the energetically favourable adsorption configuration. The change in the electronic properties of gallium doped graphene after O2 adsorption is also determined to understand the nature their interactions. The results show that gallium doped graphene has large adsorption energy and small binding distance, which correspond to chemical adsorption. The calculated band structure and density of states plots of gallium doped graphene before and after adsorption show dramatic changes in the electronic properties due to the strong interactions of gallium doped graphene with adsorbed O2 molecule. These results indicate that gallium doped graphene is highly reactive to molecular oxygen and hence not a suitable choice for harmful gas detection in the presence of O2.

Improved near-infrared up-conversion emission of YAG:Yb,Tm phosphor substituted by Gallium and Indium

Gallium–Indium co-substituted yttrium aluminum garnet (YAG:Yb,Tm) phosphors were synthesized by co-precipitation method. It can be seen that gallium and indium ions co-substitution didn’t change the phase of YAG. The upconversion luminescence (UCL) properties of the Gallium–Indium co-substituted (YAG:Yb,Tm) samples were measured under 980 nm excitation. The effects of different In3+concentration on the luminescence properties of Gallium–Indium co-substituted (YAG:Yb,Tm) were also investigated. The fluorescence-lifetime investigation shows that the substitution of Ga3+ and In3+ has a significant influence on energy transfer between Yb3+ and Tm3+ in the YAG samples.

Study on Structural Properties of Gallium and Titanium Doped Zinc Oxide Films Deposited by Magnetron Sputtering

Thin films of transparent conducting gallium and titanium doped zinc oxide (GTZO) were prepared on glass substrates by magnetron sputtering technique using a sintered ceramic target. The microstructural properties of the deposited thin films were characterized with X-ray diffraction (XRD). The results demonstrated that the polycrystalline GTZO thin films consist of the hexagonal crystal structures with c-axis as the preferred growth orientation normal to the substrate, and that the working pressure significantly affects the crystal structures of the thin films. The GTZO thin film deposited at the working pressure of 0.4 Pa has the best crystallinity, the largest grain size and the lowest stress.

Phase transition and electrical properties of gallium- and indium-doped Bi10Ti3W3O30

Polycrystalline samples of gallium- and indium-doped Bi10Ti3W3O30 (mixed-layer Aurivillius phase with the Ti4+ and W6+ distributed at random over the perovskite-like slabs) have been prepared by solid-state reactions, and their polymorphism and electrical properties have been studied. Doping with both In3+ and Ga3+ yields limited solid solutions and shifts the ferroelectric phase transition to lower temperatures. The heterovalent substitutions of In3+ and Ga3+ for Ti4+ and W6+ increase the oxygen vacancy concentration and, accordingly, the conductivity of the material relative to the undoped compound.

Properties of gallium- and aluminum-doped bulk ZnO obtained from single-crystals grown by liquid phase epitaxy

Bulk properties of gallium (Ga)- and aluminum (Al)-doped zinc oxide (ZnO) were studied using bulky single-crystalline thick films grown by liquid phase epitaxy (LPE). The highest possible dopant concentration was 1×10 19 cm –3 for LPE growth at around 800 °C. The electron concentration was nearly same to the Ga and Al concentrations. The donor binding energy decreased to nearly zero with an increase in dopant concentration, and electron mobility of the sample with relatively high dopant concentration (1×10 19 cm –3) was more than 60 cm 2 V –1 s –1 at room temperature. The LPE technique is a potential solution for the production of ZnO for optical applications because the well-defined excitonic luminescence could be seen from the LPE-grown-doped single-crystals.

First-principles study of the connection between structure and electronic properties of gallium

Different structures of gallium have been studied by means of density-functional theory. The density of states of orthorhombic $\ensuremath{\alpha}\text{-Ga}$, the only elemental solid exhibiting both metallic and molecular characters at zero pressure, shows a pseudogap at the Fermi energy. Complex analysis of the relation between lattice structure and the corresponding electronic properties allows us to throw light upon an origin of the pseudogap. We have found that the free-electron-like behavior which is a property of the high-pressure bct and fcc phases of gallium depends strongly on the arrangement of atoms in the buckled planes, one of the building blocks of the orthorhombic gallium.

Liquid Gallium: Potential Uses as a Heat-Transfer Agent

This paper deals with potential uses of gallium, as well as the most important gallium-based alloys, as energy carriers in high-safety nuclear power plants. Experimental data are given on the thermophysical, electrophysical, chemical, acoustic, and other properties of gallium and its alloys.

Grain-boundary component in W-Ga composites: A way towards skeleton structures

Nanostructured materials consist of crystalline and grain boundary components. In the simplest case, both components are chemically identical. Here, we present the results of a study of a system consisting of a crystalline component built by A atoms (tungsten) and a grain boundary component of B atoms (gallium). Within this system, component B is in a disordered state. Most likely it exhibits an 'amorphous-like' structure, and coats the tungsten crystals uniformily with a constant thickness, thus forming a Ga skeleton structure. The non-crystalline gallium seems to undergo no first order structural phase transitions, e.g., no first order melting transition was noted when the composit was below, at or above the equilibrium melting point of Ga. The properties of gallium as grain boundary component differ significantly from those of crystalline and amorphous bulk gallium.

Synthesis of nanoparticles by reactive laser vaporization: silicon nanocrystals in polymers and properties of gallium and tungsten oxides

In this paper, we present three different examples of nanocrystals prepared by the pulsed laser vaporization–controlled condensation (LVCC) technique. First, we present some new results on the photoluminescence (PL) properties of the Si nanocrystals. One of the main goals of this work is to compare the results of the PL from the solid surface-oxidized particles with those from the incorporated particles in polymer films. We also present evidence for a novel photoreduction of the white WO 3 nanoparticles into the blue W 2O 5 following the irradiation of the particles with the second harmonic of the Nd:YAG laser at 532 nm. Finally, we report the observation of efficient blue PL from Ga oxide nanoparticles. These examples demonstrate the potential use of nanoparticles in the design of optical and photonic devices.

Properties of gallium in porous glass.

We have studied the behavior of gallium in porous glass. Except for a few lines of \ensuremath{\alpha}-Ga, the main pattern of the x ray does not fit in with any previously reported phase of gallium. By resistivity measurements, just above a superconducting transition, an anomalous peak at 6.3 K was observed. Lack of x-ray patterns of \ensuremath{\beta}-Ga and \ensuremath{\delta}-Ga suggests that the 6.4 K transition might be due to a new phase of gallium or a \ensuremath{\beta} phase in strong disorder. \textcopyright{} 1996 The American Physical Society.

Calculations of the electronic structure and properties of gallium and arsenic compounds by the MINDO/3 method

Calculations of the electronic structure and properties of gallium and arsenic compounds by the MINDO/3 method

Electronic Transport Properties of Gallium: Harrison's Method

Electronic Transport Properties of Gallium: Harrison's Method

Thermoelectric Effects Across Solid-Liquid Gallium Interface

ABSTRACTA novel technique is described for directly measuring the Seebeck coefficient across the solid-liquid interface of gallium as a function of temperature and crystallographic orientation. The results are compared with those calculated from the absolute thermoelectric power of solid and liquid gallium. The temperature ranges for the measurements were 248 to 302K for solid gallium, and 278 to 353K for the liquid; the liquid was supercooled up to 25K. The effect of crystal orientation on the thermoelectric power of gallium single crystals grown along the a, b, and c axes was investigated. The anisotropy of the thermoelectric power is discussed based on the electronic properties of gallium.

IIa-8 properties of gallium-, aluminum-, and indium-doped silicon as extrinsic detector materials

IIa-8 properties of gallium-, aluminum-, and indium-doped silicon as extrinsic detector materials

Ultrasonic investigation of gallium superconducting properties

The superconducting energy gap of gallium has been determined along the three principal crystallographic axes from the temperature dependence of the attenuation of longitudinal ultrasonic waves with frequencies in the range 10-150 MHz. Like many other physical properties of gallium, the gas was found to be highly anisotropic. A self-consistent method was developed and used in order to determine the part of ultrasonic attenuation caused by electron-phonon interactions. An abnormal peak of attenuation, for which no explanation can be given, was observed for propagation along b axis. Finally, the investigation of transition temperature against magnetic field has allowed the discontinuity of specific heat at the critical temperature to be estimated.