Isovalent indium doping was employed in order to decrease the deep level concentration in n-type GaAs:S films grown by the vapour phase epitaxy in a chloride system. The EL2 electron trap was found to be the dominant deep level in the films with a low donor concentration. Using isovalent In doping, the concentration of this deep level was reduced from about 1 × 1014 cm−3, which was typical of the GaAs:S films, to a value less than the deep level transient spectroscopy (DLTS) sensitivity threshold (< 2.5 × 1012 cm−3). In the case of heavily sulphur doped films, a strong decrease in the deep level concentration was detected by photoluminescence when isovalent indium doping was used. The suppression of the deep-level-related lines was accompanied by an enhancement of the band-to-band radiative recombination. All the effects were found to appear in a narrow region close to an indium content of 1 × 1020 cm−3.

The manganese doping of In1−xGaxAsyP1-y(0 ≦ y ≦ 1) films grown by liquid-phase epitaxy has been investigated. A study has been made of the influence of the solid-solution composition and of the method of introducing the manganese into the solution melt on the electrical properties of the films, and also on the surface morphology, the optical absorption edge, and the mismatch of the film and substrate lattice constants. It is shown that the hole density in the films decreases with decreasing y. The reasons for this are the decrease in the distribution coefficient of the acceptor manganese (from 0.3 to 0.001), the increase in the degree of compensation of the acceptors with donors (from 0.2 to 0.9), and the increase in the acceptor ionization energy. The composition of the InGaAsP:Mn film and the morphology of its surface depend on the method of preparation of the melt, this being explained by the strong interaction of the manganese atoms with the other components of the liquid phase.

An investigation was made of the influence of isovalent doping with indium on the electrophysical properties, luminescence, dislocation density, lattice parameter, and concentration of deep EL 2 levels in epitaxial n -type GaAs:S films grown in a chloride gas-transport system. When the indium concentration was approximately 1 X 10(20) cm-3, the free-carrier mobility and the efficiency of the edge radiative recombination increased, the concentration of the EL 2 deep centers (responsible for the photoluminescence lines 1.2 and 0.9 eV) decreased, and there was a reduction in the dislocation density.

The influence of annealing at a temperature of 750–830°C on the electrophysical, luminescent, and structural characteristics of GaAs layers doped with various concentrations of tin is studied. It is shown that, for low doping levels, the layers possess properties with high thermal stability. During annealing, one observes a lowering of the concentration of electrons, a reduction of the lattice periodicity, and a change in the photoluminescence spectra of strongly-doped layers, which is explained by the process of the formation of complexes and by the decomposition of supersaturated solid solutions of impurity dopants.

Studies have been carried out on the perfection of then-AlxGa1−xSb1−yAsy (0.12⩽x⩽0.26) layer grown on GaSb substrates under different conditions of lattice matching. During the relaxation of the mechanical stresses at first a system of tilt dislocations with a density of up to 5 · 105 cm−2 is formed while in thick layers (h ∼ 20 μm) a network of misfit dislocations parallel to the heteroboundary is formed. The time required to dissolve a weighed amount of GaAs in the melt is shown to be of major importance for obtaining layers of a solid solution that are isoperiodic with the substrate. The entry of arsenic only in the initial portion of the epitaxial layer can reduce the dislocation density in the layer without decreasing the measured value of Aa. Dissolution of a weighed amount of GaAs in a Ga + Sb melt for two hours at T=730–750°C is sufficient to obtain layers of AlxGa1−xSb1−yAsy solid solution that are isoperiodic with the substrate.

Studies were made of heat-treated Ni-GaAs contacts, at which, prior to the electrochemical deposition of nickel, thin layers of gallium or arsenic were deposited. The physicochemical reactions at the interfaces were investigated, as well as the electrophysical characteristics of the diodes, the morphology of the metallic coatings, and the mechanical stresses. The phase composition of the contacts and the height of the barrier are seen to be practically independent of the introduction of excess Ga or As, whereas the thermal stability of the electrical parameters of the diodes varies considerably. This difference is associated with the effect of the Ga and As sublayers on the magnitude of the mechanical stresses arising at the metal-semiconductor interface.

The electrophysical properties, the lattice constant, and the structure of sulfur doped epitaxial gallium arsenide layers were investigated using a complex of methods. The experimental data indicate that the sulfur atoms can exist in the GaAs lattice simultaneously in the number of states, namely, in the form of substitutional and interstitial solid solutions, as well as in the form of presegregations or second phase segregations. The concentration of interstitial sulfur atoms increases with the overall-sulfur content in the layers. At the maximum sulfur doping level second phase segregations are formed in the layers, which leads to an anamolous decrease in the lattice constant and the electron mobility.

We describe a method for growing epitaxial layers of zinc sulfide and cadmium sulfide solid solutions on the A-side of GaAs (111) by means of separated sulfide sources in an open hydrogen iodide system. The effects of substrate temperature, amount of doping from substrate elements, and source temperatures on photoluminescence from epitaxial films of ZnxCd1-xS on GaAs are determined. By varying the growth conditions it is possible to primarily obtain a single band in the emission spectrum. The presence of a larger number of photoluminescence bands indicates that the solid solution is nonhomogeneous. The composition of the solid-solution films was determined through empirical relationships based on spectra from standard solutions. X-ray analysis was used to confirm the compositions.

We describe a method for growing epitaxial layers of zinc sulfide and cadmium sulfide solid solutions on the A-side of GaAs (111) by means of separated sulfide sources in an open hydrogen iodide system. The effects of substrate temperature, amount of doping from substrate elements, and source temperatures on photoluminescence from epitaxial films of ZnxCd1−xS on GaAs are determined. By varying the growth conditions it is possible to primarily obtain a single band in the emission spectrum. The presence of a larger number of photoluminescence bands indicates that the solid solution is nonhomogeneous. The composition of the solid-solution films was determined through empirical relationships based on spectra from standard solutions. X-ray analysis was used to confirm the compositions.

The effect of the vapor-phase epitaxy conditions on the formation of small nondislocation etch pits (SEP) in autoepitaxial gallium arsenide layers was investigated by the oblique-section metallographic technique. The investigations showed that SEP are found in n-type low-dislocation layers and are located directly in the junction region. The width of the SEP region depends on the concentration and type of dopant in the source, the type of substrate, and also on the concentration of transport agent at the system inlet. The formation of SEP in the layers involves impurity segregates of the second phase.