S. G. Mikhailov

Synthesis and magnetic properties of Mn-doped Cd0.1Zn0.9GeAs2 solid solutions

Homogeneous crystals of diluted magnetic semiconductor solid solution Zn0.9Cd0.1GeAs2 doped with 0, 1.13 and 2.65 mass% of Mn were synthesized. The grown crystals were characterized by atomic absorption and synchrotron x-ray powder diffraction analyses showing that the lattice parameter of the sample crystals are closely related to GaAs. Measurements of magnetic and transport properties were performed in the temperature range of 4–400 K using steady and pulsed magnetic fields up to B = 50 and 150 kG, respectively. The ferromagnetic Curie temperature of the sample crystals was found to be about 350 K. The magnetic ordering is attributed to the presence of MnAs clusters with mean size ~3.8 nm in the ferromagnetic phase. Influence of paramagnetic Mn2+ ions on magnetic properties of the crystals was observed only at low temperatures and was explained by the p–d interaction between charge-carrying holes and localized Mn moments.

Dilute magnetic semiconductor: Magnesium-doped Zn0.9Cd0.1GeAs2

Dilute magnetic semiconductors based on manganese-doped Zn0.9Cd0.1GeAs2 solid solution with various doping levels were synthesized. Their Curie point in 5-T magnetic field was 349 K. Ferromagnetic ordering in these semiconductors was due to MnAs nanoclusters, whose sizes were 3.7–3.8 nm.

Crystal Growth and Properties of Cd1 – xZnxAs2 Solid Solutions

Cd1 – xZnxAs2 (x = 0.03, 0.05, 0.06) single crystals are grown by the Bridgman method, and their optical absorption spectra are measured. The introduction of Zn is shown to increase the band gap of CdAs2, by up to ≃14 meV at x = 0.06. The highest content of ZnAs2 incorporated into CdAs2 is 6 mol %.

Growth and structure of ZnSnAs2 crystals

High-quality ZnSnAs2 (I) single crystals have been grown. The unit cell parameters of compound I have been refined (a = b = 5.8360(1), c = 11.686(2) Å), and its crystal structure has been determined.

Edge absorption and light propagation in single crystals of Zn1−x Cd x As2 solid solutions

The transmittance of Zn1−xCdxAs2 anisotropic single crystals in their transparency region is found to depend on the incident light polarization, photon energy, and sample thickness. This effect is shown to be associated with light scattering in Zn1−xCdxAs2, which can be understood in terms of the crystal structure of the monoclinic crystals. The fundamental absorption edge in Zn1−xCdxAs2 is dominated by an indirect forbidden transition for the E ‖ c polarization and by a direct forbidden transition for E ⊥ c.

Optical and photoelectric properties of monoclinic Zn1 − x Cd x As2 crystals

The first data are presented on the band structure of monoclinic Zn1 − xCdxAs2 crystals. The fundamental absorption edge of Zn1 − xCdxAs2 for the E ‖ c polarization is shown to be dominated by an indirect allowed transition for absorption coefficients α‖ < 6 cm−1 and by a direct allowed transition for α‖ > 6 cm−1, both transitions involving excitonic levels. The absorption edge for E ⊥ c is due to a direct forbidden transition with the participation of excitonic levels. We have determined the band gap values for these transitions in the temperature range 80–300 K, the exciton binding energy, and the ionization energies of four deep acceptor levels produced in the band gap by structural defects.

Phase Relations in the Zn3As2–ZnAs2–CdAs2–Cd3As2 System

Phase relations along the Cd3As2–ZnAs2 and Zn3As2–CdAs2 joins are studied by differential thermal analysis, x-ray diffraction, and microstructural analysis. The results, in conjunction with earlier data on the CdAs2–ZnAs2, Zn3As2–Cd3As2, Cd3As2–CdAs2, and ZnAs2–Zn3As2 binaries, are used to map out the phase diagram of the liquidus surface in the composition region Zn3As2–ZnAs2–CdAs2–Cd3As2 of the ternary system Cd–As–Zn. The ternary eutectic revealed in this region has an approximate composition of 26 at. % Cd + 65 at. % As + 9 at. % Zn and melts at 863 K.

Synthesis, structures, and electrophysical properties of single crystals of solid solutions CdGeAs2:Mn(x) and Cd0.964Zn0.036GeAs2:Mn(x)

AbstractSingle crystals of the solid solutions CdGeAs2:Mn(x) and Cd0.964Zn0.036GeAs2:Mn(x) have been grown by the vertical Bridgman method. An X-ray diffraction study has demonstrated that Cd0.964Zn0.036GeAs2 (I), Cd0.964Zn0.036GeAs2:Mn (1.5 wt%) (II), and Cd0.964Zn0.036GeAs2:Mn (2.18 wt %) (III) retain the CdGeAs2 structure (tetragonal system, space group I

Preparation and Structure of CdGeAs2 Crystals

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