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In this communication, the latest experimental results are presented on a composition of Cd1−xZnxTe1±δ, both x and δ, determined by the high-precision, vapor-pressure scanning method. The space arrangement of the single-phase solidus volume of Cd1−xZnxTe1±δ in the pressure-temperature-composition (P-T-X) phase space has been derived from direct vapor-pressure measurements in the temperature range up to 1,375 K. From the experimental data for x=0.0, 0.05, 0.1, 0.15, 0.25, 0.5, 0.75, 0.8, 0.9, and 1, the complete phase diagram of Cd1−xZnxTe1±δ was constructed. Transformation of the diagram was traced for the whole range of existence of the Cd1−xZnxTe1±δ solid solution as a function of ZnTe concentration. Increase of ZnTe in the solid solution results in the extension of the homogeneity range and a shift of the solidus toward Te, so that already for x≥0.15 the solidus does not contain the stoichiometric, (nCd+nZn):nTe=50 mol.% plane. From detailed experimental studies, maximum non-stoichiometry as a function of the temperature was determined in a wide temperature range for Te and metal solubility. Temperature dependencies of the partial pressures of vapor-phase species for different crystal compositions, XS=const, were deduced from the vapor-pressure experiment for the x=0.05 section of the diagram. From these results, relationships are derived between crystal composition, vapor pressure, and composition of the conjugated vapor.

Traveling heater method (THM) experiments on InP crystal growth from indium solution (SKAT-FD) were performed during the Russian FOTON-11 mission in October 1997. The aim of these experiments was to ascertain the effectiveness of controlling heat and mass transfer in the liquid phase by applying a rotating magnetic field (RMF). As an effort to understand the parameters influencing the crystal growth a mathematical model was developed for numerical simulation of these experiments. The SKAT-FD crystals were grown with RMF at an induction of 1 and 2 mT. As the calculations show, such magnetic fields influence remarkably the hydrodynamics of the melt, and consequently, the growth process. The change of the magnetic induction value (or switching off the RMF) led to an abrupt change of the growth rate, measured from artificial dopant striations produced in the growing crystals by the heat-pulse technique.

Semiconductor crystal growth experiments performed in Germany often used the Floating-zone technique (FZ). Recent Results of the FZ growth of Silicon, Si and Galliumantimonide, GaSb in connection with fluid dynamics will be reported.

GaSb bulk single crystals with low acceptor concentration were grown from a bismuth solution by the traveling heater method. The result is isoelectronic doping by Bi which gives a variation of the opto-electronic properties as a function of grown length as well as a pronounced microscopic segregation. Photoluminescence spectra at 4K show a decrease of the natural acceptor during growth, which is confirmed by Hall measurements. The electrical properties of this isoelectronic doped GaSb are hole concentrations and mobilities of NA − ND = 1.7 × 1016 cm−3 and μ = 870 cm2Vs at room temperature and NA­ND = 1 × 1016 cm−3 and μ = 4900 cm2/Vs at 77K, respectively. The lowest p-type carrier concentration measured at 300K is NA − ND = 3.3 × 1015 cm−3

The liquid-phase epitaxy and device fabrication of p-n and p-i-n Ga 1-x Al x Sb avalanche photodiodes is described. Breakdown voltages up to 95 V and dark currents of 10-4A/cm2have been obtained. With p-i-n diodes we have measured the impact ionization coefficients α (electrons) and β (holes) with different composition and temperature. A resonant enhancement of the hole ionization coefficient is found for x = 0.065 (300 K) where the ratio \beta/\alpha exceeds values of 20. This effect is attributed to impact ionization initiated by holes from the split-off valence band: if the spin orbit splitting Δ is equal to the bandgap energy E g , the threshold energy for hole initiated impact ionization reaches the smallest possible value ( E_{i} = E_{g} ) and the ionization process occurs with zero momentum. This leads to a strong increase of β at \Delta/E_{g} = 1 . The experimentally determined dependence of ionization coefficients on threshold energy is compared with theoretical expectations.

In0.53Ga0.47As epitaxial layers of high quality and excellent surface morphology have been grown in an automated LPE system. The growth temperature was varied between 500 and 63O°C. Room-temperature Hall measurements indicated a net carrier concentration of n = 8 × 1014 cm‾3 and mobility values of µ = 13000 cm2V‾1 s‾1 at TG 617°C and n = 7.7 × 1015 cm‾3 and μ = 9800 cm2 V‾1 s‾1 at TG = 517°C, respectively.

Two metalorganic adducts (trimethylindium-trimethylarsine (CH3)3In-As(CH3)3 and trimethylgallium-trimethylarsine (CH3)3Ga-As(CH3)3) have been used for the epitaxial growth of InxGa1−xAs on InP, and GaAs, substrates at normal pressure. Epitaxial layers with net carrier concentrations of n = 2 × 1016 cm−3, μ300K = 6600 cm2/Vs (In0.53Ga0.47As/InP) and n′ = 1 × 1016 cm−3, μ′ = 3200 cm2/Vs (In0.2Ga0.8As/GaAs) have been grown.

A new metal-organic compound, a trimethyl-indium trimethyl-phosphine adduct has been used for the growth of InP epitaxial layers. The formation of unwanted polymer products during epitaxial growth could be avoided in this way. Epitaxial layers of good quality (ND − NA≃1016−1017 cm−3 were grown at a rate of 0.8 μm/h.