AlSb Compounds Research Articles

Exploring the effect of chromium doping on electronic properties, half-metallic and ferromagnetism on AlSb DMS compound through first-principles calculations

With the aim of improving and investigating magnetocaloric insights for spintronic applications, we investigated the electronic structure of Cr-doped AlSb compounds via first-principles calculations using the KKR-CPA-DFT method. Here, we investigated the stability of alloy materials as a function of magnetic contamination. A stable semimetallic ferromagnetic phase can be obtained by introducing the Cr element into AlSb, which is inherent in nonmagnetic semiconductors. The total magnetic moment of the doped material changes from 0.1167 μB to 0.716 μB for 4% and 25% Cr, respectively. Curie temperature changed to 740 K at 25% Cr concentration.
 KEY WORDS: Magnetic materials, Semiconductor, Alloys, Impurities
 Bull. Chem. Soc. Ethiop. 2024, 38(2), 297-304. 
 DOI: https://dx.doi.org/10.4314/bcse.v38i2.2

Plasmon energy and microhardness of BxAl1-xSb alloys: semi-empirical prediction

Based on the reflective index reported in the literature, the present work aims to investigate the plasmon energy, the microhardness and the homopolar band gap energy of BxAl1-xSb ternary semiconducting alloys as a function of boron concentration x in the range 0 –1. We found that both the plasmon energy and the microhardness of BxAl1-xSb alloys change gradually but not monotonically with increasing of boron concentration x from 0 to 1, while the homopolar band gap energy increases monotonically with enhancing of x. We emphasize that a boron concentration x dependent plasmon energy and microhardness between 0 and 1 is extremely unusual behavior for BxAl1-xSb alloys. Normally, both plasmon energy and the microhardness monotonically increase with increasing boron concentration x as it was mentioned in the literature. The plasmon energy of AlSb and BSb was found to be 16.14 and 15.58 eV, respectively. Our value (16.14 eV) of the plasmon energy for AlSb compound is higher than the result (13.8 eV) reported by Böer and Pohl. The minimum of the plasmon energy was found to be 14.4 eV for both B0.5Al0.5Sb and B0.625Al0.375Sb alloys. The microhardness of AlSb was found at around 7.56 GPa, while that of BSb was found to be 6.51 GPa. Similar to the plasmon energy, the minimum value of the microhardness was found to be 4.45 GPa for both B0.5Al0.5Sb and B0.625Al0.375Sb alloys.

Theoretical Prediction of Mechanical Properties of BxAl1−xSb Ternary Semiconducting Alloys

Abstract The present work aims to predict the elastic constants and other significant properties of ordered BxAl1-xSb (0 ≤ x ≤ 1) ternary semiconducting alloys. We report the initial results of the elastic stiffness constants, the bulk modulus, the aggregate shear modulus, the Cauchy ratio, the aggregate Young’s modulus, the Born ratio, the isotropy factor, the fracture toughness and the longitudinal, transverse and average sound velocities. The Debye temperature and the melting point were also predicted using two different empirical expressions. Except the Cauchy ratio, which decreases with enhancing boron content x, all other physical quantities of BxAl1-xSb alloys increase gradually and monotonically with increasing of boron concentration x in the range 0-1. Our obtained data for BSb and AlSb binary semiconducting compounds are discussed and analyzed in comparison with experimental and other theoretical values of the literature. Generally, our data for BSb and AlSb are in good agreement with other results reported previously in literature. Indeed, our obtained value (335.82 K) of the Debye temperature for AlSb compound overestimates the result (328.6 K) reported by Salehi et al. by around 2.03%, while that (1520 K) of the melting point for BSb overestimates the result (1500 K) reported recently by Bioud et al. by around 1.34%. Furthermore, to the best of our knowledge, no theoretical or experimental data were reported in the literature on the elastic constants and other properties for BxAl1-xSb alloys to compare with them.

First-principles calculations for studying effect of Tellurium (Te) doping on electronic properties, half-metallic ferromagnetism and “Curie temperature of V-doped AlSb DMS compound

The electronic structure and magnetic features of intrinsic Al1-xVxSb, AlSb1-yTey and Al1-xVxSb1-yTey Tey diluted magnetic semiconductors (DMSs) compounds at various doping concentrations of x and y have been calculated in this study using Korringa-Kohn-Rostoker coherent-potential approximation (KKR-CPA), using a coupling local-density-functional approx-imation (LDA). Our structural parameters results showed generally agreement with the previous experimental and theoretical findings. The results of DOS demonstrate that incorporation of V-3d develops a half-metallic (HM) property in our compounds with an engendered bandgap at the Fermi energy in the down-spin state. In these materials, the stability of ferromagnetism (FM) is explained by contribution of both p-d interaction and Zener's double-exchange interaction mechanisms. Accordingly, it has been shown in our studied systems that ferromagnetic (FM) ground states are easily attainable, and that the measured Curie temperature (TC) of the (V, Te)-codoped AlSb system reaches a maximum of 1142.48K (Tcmax) and is far above room temperature (RT) and to that measured of V-doped AlSb compound (Tcmax = 364.18K) This fact and the very large Curie temperature of (V, Te)-codoped AlSb compound make inevitably this material a serious candidate for future electronic applications, especially for spintronics devices.

Phase stability, pressure-induced phase transition and electronic properties of AlX (X = P, As and Sb) compounds from first principle calculations.

ABSTRACT Density functional theory (DFT) based full-potential linearized augmented plane wave (FP-LAPW) method approach has been used to investigate the phase stability, pressure-induced phase transition and electronic properties of AlP, AlAs and AlSb compounds. The study has been performed for the zinc blende (B3), rocksalt (B1), wurtzite (B4), NiAs (B8) and CsCl (B2) phases. For structural properties, the Wu-Cohen generalized gradient approximation (WC-GGA) scheme was used while for band structure calculations, in addition to WC-GGA, the modified Becke–Johnson (mBJ) scheme was also used. Results show that the zinc blende phase is most stable amongst the other considered phases. Then the numerical results of the transition pressures have been predicted. The band structure calculations reveal that these compounds adopt a metallic behavior in rocksalt, NiAs and CsCl phases whereas they are semiconductor materials in zinc blende and wurtzite phases.

Mössbauer study of rapidly solidified Al-Fe based amorphous alloys

Mossbauer spetroscopy and X-ray diffraction were used to study the structure of rapidly quenched Al88Fe5Y7, Al88Fe4Y7Sb1 and Al93Fe5Sb2 alloys. Sb addition diminishes the glass forming ability and results in precipitation of the stable AlSb compound. The X-ray amorphous Al88Fe5Y7 alloy shows a short range order resembling to the Al6Fe compound as it can be judged from the Mossbauer data.

Room temperature electrodeposition of aluminum antimonide compound semiconductor

AlSb is a group III–V compound semiconductor material that is conventionally grown by high temperature processes such as Czochralski and Bridgman methods. Development of a method to synthesize AlSb at room temperature will be more economical to help modulate the electronic properties. In this investigation, a pulsed potential electrodeposition method using a room temperature molten salt system (aluminum trichloride, AlCl 3/1-methyl-3-ethylimidazolium chloride, EMIC) with an addition of SbCl 3 is discussed. The potential pulse parameters were established by carrying out cyclic voltammetry at different concentrations of SbCl 3 and with varying molar ratios of AlCl 3/EMIC. Stoichiometric AlSb deposits were obtained from an acidic AlCl 3/EMIC (1.5:1 molar ratio) melt containing 4 × 10 −3 mol/l of SbCl 3 onto an ordered TiO 2 nanotubular template. The AlSb compound was predominantly amorphous in as-deposited condition and annealing at 350 °C for 2 h in argon transformed into crystalline phase. The AlSb deposit showed a high resistivity in the order of 10 9 Ω-cm and a defect concentration of 10 16 cm −3 which was attributed to presence of carbon. The deposits obtained from a basic melt (0.67:1 molar ratio of AlCl 3/EMIC) were enriched with antimony.

Microscopic and Electronic Structure of Semimetallic Sb and Semiconducting AlSb Fabricated by Nanoscale Electrodeposition: An in Situ Scanning Probe Investigation

The nanoscale electrocrystallization of pure Sb and the compound semiconductor AlSb on Au(111) has been studied by in situ scanning probe techniques (STM and STS) employing an ionic liquid electrolyte, {AlCl3-[C4mim]+Cl-} (1:1) containing SbCl3. The characteristic changes of the electronic structures with varying potentials have been probed for the first time by normalized differential conductance spectra, (dI/dU)/(I/U). In the underpotential deposition range of Sb the formation of two layers is observed. For the first monolayer a (square root 3 x square root 3)R30 degrees structure is determined from atomically resolved STM images. During the deposition and dissolution of the Sb monolayers characteristic wormlike or spinodal structures appear indicating surface alloying of antimony with the gold substrate. Under overpotential conditions two different Sb structures have been observed. If the deposition potential is continuously stepped to -0.1 V, Sb nanostripes form. On the other hand, randomly dispersed small clusters occur if the potential is jumped from 0.0 to -0.3 V vs Al/Al(III). Both modifications exhibit typical semimetallic behavior as shown by the STS spectra. At -1.1 V the cyclic voltammogram shows a clear reduction wave that is assigned to AlSb compound formation. Deposits in this potential range are characterized by a homogeneous distribution of clusters with diameters of approximately 20 nm. Conductance spectra of these clusters exhibit the main features of the electronic structure of the bulk semiconductor AlSb, with a band gap of 2.0 +/- 0.2 eV. Electrodeposition experiments on both sides of the compound deposition potential show a strong doping effect that is manifest in the corresponding conductance spectra.

Formation of compound semiconductor clusters by spontaneous alloying

Alloying behavior of antimony atoms into indium-cored aluminum clusters has been studied by in-situ measurements of transmission electron microscopy. When antimony is vapor-deposited onto aluminum clusters with an indium core of about 4 nm in mean diameter, antimony atoms quickly dissolve only into the shell-shaped region of aluminum to form the polycrystalline AlSb compound, and no alloying takes place in the indium core. Upon depositing antimony onto aluminum clusters with an indium core of about 1 nm in mean diameter, antimony atoms quickly dissolve into the shell-shaped region of aluminum to form an amorphous Al 0.5Sb 0.5 alloy.

Chemical reactions at solid-solid interfaces induced by pulsed laser annealing

Al thin films (thickness < 1000 Å) evaporated on the (111) face of an Sb single crystal, and Al-Sb multilayer thin films (thickness < 1000 Å) evaporated on glass and quartz substrates were irradiated in UHV by the pulsed beam of an excimer laser. The samples were characterized in-situ during the growth of the films and after the irradiations by Auger and photoelectron spectroscopies without breaking the vacuum, and later, by scanning electron microscopy. The formation of the AlSb compound is observed above the fluence threshold previously reported. Lateral transport of matter and inhomogeneous reaction are observed after irradiation of the Al films deposited on Sb crystals, leading to the formation of an inhomogeneous surface with holes and particles. A strong chemical reaction between the substrate and the films also leads to a partial oxidation of the film evaporated on quartz or glass. We observed the same behaviour under the IR laser beam from a Q-switched Nd:YAG laser. One has taken advantage of fast thermal processes of thin films induced by pulsed or scanned CW laser beams for applications like synthesis of compounds by laser alloying, oxidation of thin films, planarization, and phase changes in optical data storage media. The relevant parameters needed to predict the evolution of the film/substrate interface under strong laser irradiation using the thermal model are not only: (i) the thermal properties of the substrate, and (ii) the optical characteristics of the film-substrate system, but also (iii) the chemical stability of the interface, and (iv) the free surface energies of the substrate and of the film, at least above the melting fluence threshold or if thermal cycling is expected over large periods of time.

The influence of thermal pressure on the equation of state for AIP, AlAs and AlSb compounds

The lattice dynamical effect on the Helmholtz free energy and on the equation of state for AIP, AlAs and AlSb compounds are studied in the method of lattice dynamics based on our presented binding force. The resultant Helmholtz free energy and thermal pressure from lattice vibrational term are temperature-dependent, and dynamical contributions to free energy are small compared with the static crystal energy. Then, the effect of the thermal pressure is quantitatively important to the equation of state at high temperatures, and the revised version of the volume scale for the pressure-volume relation is necessary when considering the thermal pressure.

Compression Effect on Elastic Coefficients of AlP, AlAs, and AlSb Compounds

Compression Effect on Elastic Coefficients of AlP, AlAs, and AlSb Compounds

Equation of state and compression effect on the bulk modulus of AlP, AlAs and AlSb compounds

The equation of state and the pressure effect on the bulk modulus of AlP, AlAs and AlSb are studied from the electronic theory of solids by using our presented binding force, although not reported experimentally. The obtained results of the pressure-volume relations involving the pressure- induced phase transition are useful to estimate the experimental data of these compounds. The obtained bulk modulus increases with the crystal volume compressed, and the pressure derivative of the bulk modulus for AlP, AlAs and AlSb is estimated theoretically.

Prediction of high-pressure NaCl-phase of AlP, AlAs and AlSb compounds

The phase transition of AlP, AlAs and AlSb under pressure is studied from the electronic theory of solids by using our presented binding force, which includes mainly covalent interactions in the pseudo-potential formalism and partially ionic interactions. The partially ionic forces bring the essential contributions to the high-pressure phase of AlP, AlAs and AlSb, and stabilize the NaCl-type structure for the high-pressure phase of these compounds, although not reported experimentally. Then, numerical results for the transition pressure, the volume discontinuity, the transition heat and the lattice parameter in NaCl-type lattice of AlP, AlAs and AlSb are predicted theoretically.