The simultaneous crystallization of ZnSnP2/ZnSiP2 — a heterocombination

In the solution growth of ternary semiconductors tin can be used as solvent. In this case the phase purity resp. the generation of a solid solution of the reaction products obtained is of interest. This problem was investigated using the growth of ZnSiP₂ from tin solutions. For characterizing the phases obtained by the growth X-ray diffraction. Mössbauer spectroscopy, electronoprobe analysis, luminescence spectroscopy, DTA-measurements and electrical measurements were used. The results of these measurements allow the following statements within the limits of measuring.

• 1 The growth of the pure ZnSiP₂ from tin melts is possible.
• 2 The phases ZnSnP₂ and ZnSiP₂ are generated side by side by a nonstoichiometric amount weighed of silicon.
• 3 The solubility of ZnSnP₂ in ZnSiP₂ or reverse could not be pointed out.
• 4 The precipitation of ZnSnP₂ on ZnSiP₂ takes place epitaxially.

     

X-ray diffraction studies of interdiffusion in InP?GaP powder blends

Interdiffusion in the InP GaP solid solution system is investigated by means of X-ray diffraction of annealed powder blends. An activation energy of Q = (3.15 ± 0.3) eV for the interdiffusion process in the temperature interval 650… 725 °C was found. Diffusion parameters obtained by means of this method for InP GaP and InAs GaAs are discussed on the basis of lattice and atomic characteristics.     

Contribution to the Si doping of bridgeman GaAs

GaAs: Si with different doping level was grown by the gradient freeze method. The crystals were characterized by structural, electrical and optical methods concerning especially the dependence of the epd and the compensation degree on the carrier concentration.     

Porous crosslinked spherical resins for diversified applications: packing materials for size exclusion chromatography

Improvements in the synthesis of porous polymers for different applications have been carried out in our laboratory. Beads of poly(styrene-co-divinylbenzene) with morphology adequate to the application at hand were prepared. Packing materials for size exclusion chromatography (SEC) weve prepared by single-step swelling and polymerization (SSWP) and by modified suspension polymerization (MSP). High values of exclusion limit (10⁶ and 8.0x10⁶) were attained for SEC columns packed with poly(styrene-co-divinylbenzene) synthesized using high proportions of polystyrene, as porogen agent and divinylbenzene. The maximum values of exclusion limits were attained for SEC columns packed with beads prepared by SSWP method.     

Influence of film structure on the electron energy loss spectra of GaAs thin films

Energy loss measurements of fast electrons on GaAs yielded values for the plasma oscillation, interband transitions and the dielectric function in the region 5 — 30 ev. The results are discussed in comparison with literature statements. It is dealt especially with the influence of the degree of crystallinity of examined GaAs-films on the energy loss spectrum and the quantities derived from it.     

Elastic debye temperature of compounds with sphalerite structure

Elastic Debye temperatures θ_EL of the semiconducting compounds A^IIIB^V, A^IIB^VI and CuCl are evaluated from second order elastic constants C_ik available from the literature. The dependence of θ_EL on temperature is given. The results at 0 K are compared with those calculated from low temperature measurements of specific heat. Generally, the agreement between these values is better than found in the literature up to now.