Application of the holographic interferometer for modeling of processes in a vapor phase epitaxy reactor

Using holographic interferometry techniques, it is possible to visualize flows in the gas phase and obtain quantitative data about vapor phase density distribution in a given volume. The possibility of using this approach for monitoring processes in a vapor phase epitaxy (VPE) reactor has been studied using an experimental setup comprising a reactor chamber with two transparent windows, a real-time holographic interferometer, a gas supply system, and a system for visual observation of the gas flows. The results show good prospects of this method for optimization of the reactor design and the VPE process parameters.     

Thermoelectric Properties of nGeTe · mSb2Te3Layered Compounds

The Hall coefficient, electrical conductivity, and thermoelectric power of Ge₃Sb₂Te₆, Ge₂Sb₂Te₅, GeSb₂Te₄, and GeSb₄Te₇were measured over a wide temperature range (R _Hand from 77 to 800 K and Sfrom 90 to 450 K). The carrier concentration was varied via compositional changes within the homogeneity regions of the compounds. All of the materials studied were found to be p-type. Some of the alloys have a low lattice thermal conductivity and are, therefore, candidate p-type thermoelectric materials. The temperature-dependent hole mobility data suggest that both acoustic phonons and point defects contribute to the scattering of charge carriers at low temperatures.