N. A. Economou

On the phase diagram of the Ga-Te system in the composition range 55 at % Te

Monoclinic Ga-Te was heated in the electron microscope. At about 800° C decomposition was observed and after cooling down to room temperature, two compounds were identified: the fcc Ga2Te3 and the Ga3Te4, for which a trigonal structure was identified. A relation between the three structures of Ga-Te, Ga3Te4 and Ga2Te3 is put forward.

Growth of Germanium Monoselenide single crystals

Abstract GeSe single crystals are grown in an ampoule by vapour transport. The mp and the orthorhombic symmetry was confirmed. Transmission electron microscope studies revealed that the crystals are composed of areas of simple structure and areas were a more complicated structure is evident. This structure, by lattice image techniques was proved to contain periodic spacing anomalies, with walls lying on (110) planes.

The ordered state of In3Te4

The composition of In3Te4 has been established as a single-phase material. Single crystals of this material have been prepared and its structure has been identified as tetragonal with lattice parameters a0 = b0 = 6.173 and c0 = 12.438 A. The stability of the structure has also been investigated.

Ultra-low pressure chemical vapour deposition of polycrystalline and amorphous silicon

The deposition of undoped polycrystalline and amorphous silicon in an ultra-low pressure chemical vapour deposition system capable of achieving operating pressure of 0.03 Pa is discussed. It is found that at deposition temperatures in the region of 630 °C and reactor pressures of less than 1.3 Pa very large grained polycrystalline silicon films are obtained, and in this regime the growth rate is independent of the reactor pressure. Excellent uniformity is obtained and the process can be easily scaled up for large substrates and high volume batch production.

On the high temperature electrical resistivity behaviour of Cu55-Ni45 alloy

Resistivity measurements supplemented with electron microscopy investigation in a Cu55-Ni45 alloy are reported, in the temperature range 273–700 K. An anomalous high temperature resistivity minimum is observed at 673 K whereas at the same temperature diffuse intensity maxima appear. It is suggested that the resistivity minimum could be attributed to the effect of short range order cluster formation.