Millimeter and Submillimeter Wave ESR System: Using 30 T Pulsed Magnetic Field

New systems for millimeter and submillimeter wave ESR have been developed in Kobe University. In the previous system the pulsed magnetic field was limited up to 17 T in the temperature range from 1.8 to 86 K. Using the new systems, we can measure in the field range up to 30 T in the temperature range from 1.8 K to 4.2 K and from 18 K to room temperature. The resolution of the magnetic field has been also improved in the new ESR system. The details of our new ESR systems are presented. In addition, the measurements of Yb₂Cu₂O₅ using these new systems are presented.

     

Submillimeter wave ESR measurements of metamagnetic Y2Cu2O5

Submillimeter wave ESR system in Kobe University is presented. It covers the frequency region from 60 to 383GHz and can apply the pulsed magnetic field up to 30T. The measurement of Y₂Cu₂O₅ single crystals using our system is presented.     

Development of a Millimeter-Wave Electron-Spin-Resonance Measurement System for Ultralow Temperatures and Its Application to Measurements of Copper Pyrazine Dinitrate

We have developed a millimeter-wave electron-spin-resonance (ESR) measurement system using a ³He-⁴He dilution refrigerator for the ultralow-temperature range below 1 K. The currently available frequency range is 125–130 GHz. This system is based on a Fabry-Pérot-type resonator (FPR) that is composed of two mirrors. The frequency can be changed by adjusting the distance between the mirrors using a piezoelectric actuator installed at the bottom of the resonator. A homodyne detection system with an InSb detector is built into the low-temperature section of the ³He-⁴He dilution refrigerator; this system provides high sensitivity. Using this system, we performed ESR measurements on a Heisenberg quantum-spin chain—copper pyrazine dinitrate, Cu(C₄H₄N₂)(NO₃)₂—over the temperature range from 6.6 down to 0.25 K. The ESR lines change continuously with decreasing temperature. Our results suggest that the ESR spectrum of copper pyrazine dinitrate may be useful as a temperature sensor for the very low-temperature range.     

Tunneling effects in tilted magnetic fields in n-InGaAs/GaAs structures with strongly coupled double quantum wells

The effects of tunneling between two parallel two-dimensional electron gases in n-InGaAs/GaAs nanostructures with strongly coupled double quantum wells with a change in the in-plane component of a tilted magnetic field (up to B _‖ = 9.0 T) in the temperature range T = 1.8–70.0 K are investigated. A nonmonotonic temperature dependence of the inverse quantum lifetime τ _q ^? (T) is obtained from analysis of the dependence of the longitudinal resistance on the parallel component of the tilted magnetic field at fixed temperatures, ρ _xx (B _‖, T). The quadratic portion of this dependence is found to be due to the contribution of inelastic electron-electron scattering. The decrease in the inverse quantum lifetime τ _q ^? (T) at T > 0.1T _F cannot be described within known theories; it seems, it is not related to the processes of electron momentum relaxation.     

Photoinduced Magnetization with a High Curie Temperature and a Large Coercive Field in a Co‐W Bimetallic Assembly

The crystal structure, magnetic properties, and temperature‐ and photoinduced phase transition of [{Co^II(4‐methylpyridine)(pyrimidine)}₂{Co^II(H₂O)₂}{W^V(CN)₈}₂]·4H₂O are described. In this compound, a temperature‐induced phase transition from the Co^II (S = 3/2)‐NC‐W^V(S = 1/2) [high‐temperature (HT)] phase to the Co^III(S = 0)‐NC‐W^IV(S = 0) [low temperature (LT)] phase is observed due to a charge‐transfer‐induced spin transition. When the LT phase is irradiated with 785 nm light, ferromagnetism with a high Curie temperature (T_C) of 48 K and a gigantic magnetic coercive field (H_c) of 27 000 Oe are observed. These T_C and H_c values are the highest in photoinduced magnetization systems. The LT phase is optically converted to the photoinduced phase, which has a similar valence state as the HT phase due to the optically induced charge‐transfer‐induced spin transition.     

Calculation of the mutual capacitance of nanoobjects

A method for determination of the mutual effective capacitance for molecules, molecular clusters, and nanoparticles on the basis of the quantum-mechanical calculation of the interaction energy of nanoscale charged objects is proposed. The mutual effective capacitance for pairs of similar molecules (carborane C₂B₁₀H₁₂, fullerene C₆₀, and molecular cluster Pt₅(CO)₆(PPh₃)₄) with a size of 0.3 to 0.7 nm is calculated for distances between these molecules from 2 to 20 nm. It is demonstrated that this method makes it possible to determine the scale of distances between nanoobjects for which it is necessary to take into account quantum corrections.     

Superconducting Properties of (M x /YBa2Cu3O7−δy )N Multilayer Films with Variable Layer Thickness x

The superconducting properties of (M _x /YBa₂Cu₃O_7−δy )_N multilayer films were studied for varying layer thickness x. Different M phases were examined including green-phase Y₂BaCuO₅ (211), Y₂O₃, BaZrO₃, CeO₂, SmBa₂Cu₃O_7−δ (Sm123), brown-phase La₂BaCuO₅ (La211), and MgO. Multilayer (M _x /YBa₂ Cu₃O_7−δy )_N structures were grown by pulsed laser deposition onto SrTiO₃ or LaAlO₃ single-crystal substrates by alternate ablation of separate YBa₂Cu₃O_7−δ (123) and M targets, at temperatures of 750°C to 790°C. The x layer thickness was varied from 0.1 nm to 4.5 nm, and the y 123 layer thickness was kept constant within a given range of 10 to 25 nm. Different M phase and x layer thicknesses caused large variations of the microstructural and superconducting properties, including superconducting transition (T _c), critical current density as a function of applied magnetic field J _c(H), self-field J _c(77 K), and nanoparticle layer coverage. Strong flux-pinning enhancement up to 1 to 3x was observed to occur for M additions of 211 and BaZrO₃ at 65 to 77 K, Y₂O₃ at 65 K, and CeO₂ for H < 0.5 T. BaZrO₃ had a noticeably different epitaxy forming smaller size nanoparticles ∼8 nm with 3 to 4x higher areal surface particle densities than other M phases, reaching 5 × 10¹¹ nanoparticles cm⁻². To optimize flux pinning and J _c (65 to 77 K, H = 2 to 3 T), the M layer thickness had to be reduced below a critical value that correlated with a nanoparticle surface coverage <15% by area. Unusual effects were observed for poor pinning materials including Sm123 and La211, where properties such as self-field J _c unexpectedly increased with increasing x layer thickness.     

Nature of the diamagnetic maximum in the temperature dependences of the magnetic susceptibility of crystals of (Bi2 ? x Sb x )Te3 alloys (0 < x < 1)

The temperature dependences of the magnetic susceptibility ?? of crystals of (Bi_{2 ? x} Sb _x )Te₃ alloys (0 < x < 1) are studied using a SQUID magnetometer in the temperature range from 2 to 400 K with the parallel and perpendicular orientations of the vector of magnetic field strength H relative to the trigonal axis of the crystal C ₃ (H ?? C ₃ and H ?? C ₃). It is found that the diamagnetic susceptibility of the samples with x = 0.2 (Bi_1.8Sb_0.2Te₃) and x = 0.5 (Bi_1.5Sb_0.5Te₃) increases in the range from 50 K to temperatures preceding the emergence of intrinsic conductivity (250 K). It is found that the diamagnetic maximum manifests itself in the same temperature range, in which an anomalous increase in the Hall coefficient is observed. It is shown that the nature of the diamagnetic maximum is associated with the nonparabolicity of the energy spectrum of light diamagnetic holes, a decrease in whose concentration is accompanied by a decrease in their effective masses, which provides an increase in the diamagnetic susceptibility with increasing temperature. These results are confirmed by the dynamics of the temperature variation in the resonance frequency of plasma oscillations of free charge carriers.     

Low-temperature pulsed CVD of ruthenium thin films for micro- and nanoelectronic applications,Part 1: Equipment and methodology

An overview is presented of the low-temperature pulsed CVD equipment and techniques used in these experiments for making ruthenium thin films with Ru(CO)₃(C₆H₈) as the first precursor and NH₃, H₂, or N₂O as the second precursor.     

[Fe3(HCOO)6]: A Permanent Porous Diamond Framework Displaying H2/N2 Adsorption,Guest Inclusion,and Guest‐Dependent Magnetism

The porous magnet [Fe₃(HCOO)₆], the iron member of the [M₃(HCOO)₆] family (where M = Mn, Fe, Co, Ni, etc.), based on a diamond framework consisting of Fe‐centered FeFe₄ tetrahedral nodes, is prepared successfully by using a solution‐chemistry method. The as‐prepared compound, [Fe₃(HCOO)₆](CH₃OH)_1.5(H₂O)_0.5 ( 1 ‐ parent ), exhibits facile removal of its guests, methanol, and water, to give the desolvated framework [Fe₃(HCOO)₆] ( 2 ‐ empty ) that displays permanent porosity and thermal stability up to 270 °C. The flexibility of the framework and the amphiphilic nature of the surface of the pores consisting of both C–H and O arrays allows 2 ‐ empty to take up significant H₂ and N₂ at liquid‐nitrogen temperatures and a wide spectrum of both polar and nonpolar guests of different sizes. A series of guest‐inclusion compounds, [Fe₃(HCOO)₆](I₂)_0.84 ( 3 ‐ iodine ), [Fe₃(HCOO)₆](C₄H₈O) ( 4 ‐ THF ), [Fe₃(HCOO)₆](C₄H₄O) ( 5 ‐ furan ), [Fe₃(HCOO)₆](C₆H₆) ( 6 ‐ benzene ), [Fe₃(HCOO)₆](CH₃CN) ( 7 ‐ acetonitrile ), and [Fe₃(HCOO)₆]((CH₃)₂CO) ( 8 ‐ acetone ) are successfully prepared by vapor diffusion of the guest into the pores of 2 ‐ empty and their structures are characterized by using single‐crystal X‐ray crystallography. Zigzag molecular arrays of the guest are formed in the confined channels of the host framework, and the weak hydrogen‐bonding provides the main host–guest interaction. All the compounds show 3D long‐range magnetic ordering and guest‐modulated Curie temperatures, coercive fields, and remnant magnetization as a consequence of the subtle rearrangement of the magnetic framework that conforms to the size of the guests and the difference in host–guest interactions. A possible magnetic structure of the framework is proposed to account for magnetic competition and geometrical frustration. The thermal and spectroscopic properties of the compounds are also reported.     

Apparent Potential Difference Boosting Directional Electron Transfer for Full Solar Spectrum‐Irradiated Catalytic H2 Evolution

Directional charge transfer among nanolayers of graphitic carbon nitride (g‐C₃N₄) is still inefficient because of the interlayer electrostatic potential barrier, which tremendously restricts the utilization of charges in conversion of solar energy into fuel. Herein, an apparent potential among nanolayers is introduced to boost interlayer electron transfer by curving planar g‐C₃N₄ nanosheets into carbon nitride square tubes (C₃N₄Ts), and Ni₂P nanoparticles as electron acceptors are loaded on C₃N₄Ts (Ni₂P/C₃N₄Ts) for highly efficient H₂ evolution. Study results present H₂‐evolution efficiency over the constructed Ni₂P/C₃N₄Ts up to 19.25 mmol g^?1 h^?1 with a large number of visible H₂ bubbles, which is more than 1.9 and 2.6 times of that over g‐C₃N₄ supported 1 wt%Pt and 3 wt%Pd, respectively. Density functional theory (DFT) and characterizations reveal efficient directional transfer through C₃N₄T interlayer (001) to Ni₂P (111) is achieved under the apparent potential difference of C₃N₄Ts, which therefore ensures the high H₂‐evolution performance of Ni₂P/C₃N₄Ts. These results in the field of material engineering supply a novel strategy to boost directional charge transfer for solar energy conversion efficiency by introducing apparent potential difference.     

Phase relations in Cu- RO1.5- O (R < Ho,Er, Yb) and gibbs energy of formation of Cu2R2O5 (R < Ho,Er, Yb) between 1000 and 1325K

Phase relations in Cu-RO_1.5-O(R < Ho,Er,Yb) ternary systems at 1273K have been established by isothermal equilibration of samples containing different ratios of Cu:R(R < Ho,Er,Yb) in flowing air or high purity argon atmosphere for four days. The samples were then rapidly cooled to ambient temperature and the coexisting phases were identified by powder x-ray diffraction analysis. Only one ternary oxide, Cu₂R₂O₅(R < Ho,Er,Yb) was found to be stable. The chemical potential of oxygen for the coexistence of the three phase assemblage, Cu₂O + R₂O₃ + Cu₂R₂O₅(R < Ho,Er,Yb) has been measured by employing the solid-state galvanic cells,< (−) Pt, Cu₂O + Ho₂O₃+ Cu₂Ho₂O₅//CSZ//Air (Po₂< 2.12 × 10⁴ Pa), Pt (+) (−) Pt, Cu₂O + Er₂O₃+ Cu₂Er₂O//CSZ//Air (Po₂< 2.12 × 10⁴ Pa), Pt (+) (−) Pt, Cu₂O + Yb₂O₃ + Cu₂Yb₂O₅//CSZ//Air (Po₂ < 2.12 × 10⁴ Pa), Pt (+) in the temperature range of 1000 to 1325K. Combining the measured emf of the above cells with the chemical potential of oxygen at the reference electrode, using the Nernst relationship, gives for the reactions, 2Cu₂O(s) + 2Ho₂O₃(s) + O₂(g) → 2Cu₂Ho₂O₅(s) (1) 2Cu₂O(s) + 2Er₂O₃(s) + O₂(g) → 2Cu₂Er₂O₅(s) (2) and 2Cu₂O(s) + 2Yb₂O₃(s) + O₂(g) → 2Cu₂Yb₂O₅(s) (3) δΜo₂ = −219,741.3 + 145.671 T (±100) Jmol⁻¹ (4) δΜo₂ = −222,959.8 + 147.98 T(±100) Jmol⁻¹ (5) and δΜo₂ = −231,225.2 + 151.847 T(±100) Jmol⁻¹ (6) respectively. Combining the chemical potential of oxygen for the coexistence of Cu₂O + R₂O₃ + Cu₂R₂O₅(R− Ho,Er,Yb) obtained in this study with the oxygen potential for Cu₂O + CuO equilibrium gives for the reactions, 2 CuO(s) + Ho₂O₃(s) → Cu₂Ho₂O₅(s) (7) 2 CuO(s) + Er₂O₃(s) → Cu₂Er₂O₅(s) (8) and 2 CuO(s) + Yb₂O₃(s) → Cu₂Yb₂O₅(s) (9) δG‡ < 22,870.3 − 23.160 T (±100) Jmol⁻¹ (10) δG‡ < 21,261.1 − 22.002 T (±100) Jmol⁻¹ (11) and δG‡ < 17,128.4 - 20.072 T (±100) Jmol^-1 (12) It can be clearly seen that the formation of Cu₂R₂O₅R < Ho,Er,Yb) from the component oxides is endothermic. Further, Cu₂R₂O₅(R < Ho,Er,Yb) are an entropy stabilized phases. Based on the results obtained in this study, the oxygen potential diagram for Cu-R-O(R < Ho,Er,Yb) ternary system at 1273K has been composed.     

Analysis of reactor geometry and diluent gas flow effects on the metalorganic vapor phase epitaxy of AIN and GaN thin films on α(6H)-SiC substrates

The influence of diluent gas on the metalorganic vapor phase epitaxy of AlN and GaN thin films has been investigated. A computational fluid dynamics model using the finite element method was employed to improve film uniformity and to analyze transport phenomena. The properties of AlN and GaN thin films grown on α(6H)-SiC(0001) substrates in H₂ and N₂ diluent gas environments were evaluated. Thin films of AlN grown in H₂ and N₂ had root mean square (rms) roughness values of 1.5 and 1.8 nm, respectively. The surface and defect microstructures of the GaN thin films, observed by scanning and transmission electron microscopy, respectively, were very similar for both diluents. Low temperature (12K) photoluminescence measurements of GaN films grown in N₂ had peak intensities and full widths at half maximum equal to or better than those films grown in H₂. A room temperature Hall mobility of 275 cm²/V·s was measured on 1 μm thick, Si-doped, n-type (1×10¹⁷ cm⁻³) GaN films grown in N₂. Acceptor-type behavior of Mg-doped GaN films deposited in N₂ was repeatably obtained without post-growth annealing, in contrast to similar films grown in H₂. The GaN growth rates were ∼30% higher when H₂ was used as the diluent. The measured differences in the growth rates of AlN and GaN films in H₂ and N₂ was attributed to the different transport properties of these mixtures, and agreed well with the computer model predictions. Nitrogen is shown to be a feasible alternative diluent to hydrogen for the growth of AlN and GaN thin films.     

Magnetic susceptibility of (Bi2 ? xSbx)Te3 (0 < x < 1) alloys in the temperature range 2 to 50 K

The superconducting quantum interferometer device with Josephson junctions (SQUID magnetometer) is used to study the temperature dependences of the magnetic susceptibility of (Bi_2−x Sb _x )Te₃ (0 < x < 1) alloy crystals in the temperature range 2 to 50 K, at the magnetic field vector H orientations H | C ₃ and H ⊥ C ₃ with respect to the crystal trigonal axis C ₃. It is found that the magnetic susceptibility of the ion core of the samples under study is χ ^G = −0.35 × 10⁻⁶ cm³/g, the contribution of lattice defects to magnetic susceptibility can be disregarded, and the contribution of free carriers is of a diamagnetic nature in the entire studied temperature range. It is shown that the contribution of free carriers to the resulting magnetic susceptibility and its anisotropy can be described within the Pauli and Landau-Peierls approach. In calculating the magnetic susceptibility, taking into account the constant concentration of free carriers in the state of pronounced degeneracy, it is found that the temperature dependence of the anisotropic effective masses varies with crystal chemical composition. This is possibly associated with the complex structure of the valence band and its variation as the Sb₂Te₃ content in the alloy increases.     

Magnetoresistance and magnetization studies of the layered magnanite system La<Subscript>1.2</Subscript>Ca<Subscript>1.8</Subscript>Mn<Subscript>2−x</Subscript>Ru<Subscript>x</Subscript>O<Subscript>7</Subscript> (0 ≤ x ≤ 1)

We report here the results of magnetotransport and electrical resistivity (ρ) measurements in the temperature range of 4.2–320 K and in the presence of magnetic fields up to 10 T on the Ru-doped, bilayered manganite system, La_1.2Ca_1.8Mn_2−xRu_xO₇ (0≤x≤1). We find that the Ru doping affects the magnetotransport properties considerably. The ρ versus H data were analyzed by fitting the data to the power-law equation, ρ = ρ₀ − αHⁿ. The isothermal magnetoresistance (MR) versus H curves taken up to ± 10 T are highly symmetrical, and their curvature changes from concave up to concave down as the temperature increases. The MR, defined as [ρ(H) − ρ(0)]/ρ(0), is found to increase with Ru doping from 58% to 64% up to x=0.1 and to decrease to 45% for the x=1 sample at 10 K. Analysis of the ρ-T data below 30 K shows that, at low temperature, the system behaves like a disordered metal.     

Enhancing Photoluminescence Quantum Yield in 0D Metal Halides by Introducing Water Molecules

Enhancing photoluminescence quantum yield (PLQY) is one of the most important issues in photoluminescent materials. Herein, a molecule design strategy to improve the PLQY in 0D metal halides is proposed. Two new lead‐free organic–inorganic metal halide hybrids with broadband orange emissions have been prepared with a PLQY increase of 57% from (C₆N₂H₁₆)SbCl₅ ( I ) to (C₆N₂H₁₆)SbCl₅?H₂O ( II ) by introducing H₂O molecules. These two compounds have very similar inorganic frameworks, except that the incorporation of water molecules in II increases the distance between the [SbCl₅] polyhedra. It is revealed that the increase of PLQY is mainly attributed to the generation of more local photoelectrons resulting from the additional water molecules. This work provides a new insight to improve the PLQY for 0D environmentally friendly organic–inorganic metal halide hybrids and is beneficial for further photoluminescent material exploration.     

Structure and soft magnetic properties of Fe-Co-Ni-based multicomponent thin films

Soft magnetic thin films with suitable uniaxial anisotropy and high saturation magnetization are required for high frequency applications, since the ferromagnetic resonance frequency (f_FMR) is proportional to the multiplication of the saturation magnetization and anisotropy magnetic field. In this study, multicomponents of Fe-Co-Ni-based soft magnetic thin films were deposited on the Si substrate by radio frequency (RF) magnetron sputtering with various Ar/N₂ ratios at room temperature. The composition, crystal structure, surface morphology, and magnetic domain were analyzed. Without nitrogen doping, the domain of the magnetic thin film was arranged randomly. The effect of N₂ content in the thin film on the magnetic properties was evaluated and further discussed. Magnetic properties, including saturation magnetization (M_s) and coercivity (H_c), were determined. The saturation magnetization of the undoped magnetic thin film was around 1.3 T. However, when the nitrogen was added, the magnitude of the anisotropy field could reach 30 Oe, while the saturation magnetization was around 1 T. It is expected that the derived magnetic thin film is a promising candidate for potential usage in high frequency inductors.     

Facile “Spot‐Heating” Synthesis of Carbon Dots/Carbon Nitride for Solar Hydrogen Evolution Synchronously with Contaminant Decomposition

The use of solar energy to produce the clean hydrogen (H₂) energy from water splitting is a promising means of renewable energy conversion. High activation barriers for O₂ generation associated with the rate‐limiting steps require utilization of noble metal‐based cocatalysts, which complicates the fabrication procedure and compromises the stability of the catalyst. Here, a homogenous “spot heating” approach is designed via the ultrasonic cavitation effect for evenly embedding highly crystalline carbon quantum dots (CQDs) on 2D C₃N₄ nanosheets. Based on density functional calculations and electrochemical experiments, the optimal introduction of CQDs into C₃N₄ not only extends light absorption spectrum, but also reduces effective mass of electrons (e^?), facilitating photocarrier transport from excited sites. And, more importantly, the well‐organized CQDs with superior peroxidase mimetic activity can increase catalytic H₂ production through the process of (i) 2H₂O → H₂O₂ + H₂; (ii) H₂O₂→2 ? OH; (iii) ?OH + bisphenol A→ Final Products, with H₂ production rate (152 µmol g^?1 h^?1) several times higher than that for pure C₃N₄. This work demonstrates an ideal platform for efficient H₂ production with synergetic organic contaminant degradation, thereby opening possibilities for coupling energy conversion with environmental remediation.     

Magnetic-field dependence of the hopping conduction of electrostatically disordered quasi-2D semiconductor systems under the conditions for the insulator-metal percolation transition

Lateral conductance G of the metal-nitride-oxide-silicon mesoscopic transistor structures with the inversion n channel and a relatively high (no less than 10¹³ cm⁻²) concentration of integrated charges is studied versus magnetic field (up to 45 T) and potential of field electrode V _g at a temperature of 4.2 K. The characteristics of the saddle regions of the fluctuation electrostatic potential that form the mesoscopic percolation network as point quantum contacts are analyzed in the framework of the Landauer-Büttiker model. The measured features of the magnetic-field dependences of G in the low-inversion region (a transition from the positive magnetoresistive effect at G ≤ e ²/h to a relatively strong (about 100%) negative magnetoresistive effect with an increase in V _g) are related to structural modifications of percolation cluster under the action of the field effect. The dependences of G on magnetic field are in agreement with the dependences of G on V _g.     

Monoethylarsine pyrolysis mechanisms—alone and with trimethylgallium

Pyrolysis of monoethylarsine (C₂H₂AsH₂), alone and with trimethylgallium ((CH₃)₃Ga), has been studied at atmospheric pressure in a flow tube reactor using mass spectrometry. He and D₂ were selected as the carrier gases to determine the ambient effects and to isotopically label the pyrolysis products. Supplemental C₂H₅ and CH₃ radicals, produced from pyrolysis of azoethane ((C₂H₅)₂N₂) and azomethane ((CH₃)₂N₂), were added for some experiments to investigate the role of radicals in pyrolysis. No ambient effect appeared; however, the pyrolysis could be enhanced by addition of either C₂H₅ or CH₃ radicals. Enhanced pyrolysis also occurred when (CH₃)₃Ga was added. The products for pyrolysis alone and with (C₂H₅)₂N₂ were nearly identical, mainly C₂H₆ and small amounts of diethylarsine ((C₂H₅)₂AsH) and AsH₃. However, with (CH₃)₂N₂ and (CH₃)₃Ga, in addition to the major products C₂H₆ and CH₄, other CH₃-associated species were observed. These results suggest that (1) C₂H₅AsH₂ alone pyrolyzes via C₂H₅ radical reactions and (2) with (CH₃)₃Ga, CH₃ radical reactions are important decomposition pathways. Pyrolysis of (C₂H₅)₂AsH and triethylarsine ((C₂H₅)₃As), alone and with (CH₃)₂Ga, are compared. A generalized theory for pyrolysis in all three ethylarsine systems is suggested. The main role of (CH₃)₃Ga during growth of GaAs using (CH₃)₃Ga and any of the ethylarsines is probably the supply of CH₃ radicals which abstract H or C₂H₅ ligands from the ethylarsine parent molecules.