Parameters influencing the interfacial interaction between liquid gallium and single crystalline gallium arsenide were investigated under vacuum by means of the sessile-drop technique over the temperature range ,-~ 30 to 200~ In addition to their dependence on the anisotropy of the {1 1 1 } planes, contact angles in the Ga(I)lGaAs(s) system were found to be sensitive to the degree of misorientation and the direction of tilt of these planes. Furthermore, contact angles were found to be dependent on the size of the liquid drop and on the surface roughness of the substrate. In agreement with theoretical expectations the measured angles increased with increasing roughness of the GaAs surfaces. However, these angles were found to be unaffected by the presence of N2, Ar, and He atmospheres, and by the nature and concentration of charge carriers in the substrate.

The equilibrium and free surface sublimation pressures of bismuth telluride were determined by the torsion‐effusion and torsion‐Langmuir techniques, respectively. Based on a least‐square fit, the expression for the equilibrium pressure in the temperature range of 722°–828°K was found to be: logP false(normalatmfalse)=false(7.579±0.373false)−false(1.020±0.029false)104/T , where T is the absolute temperature and the given uncertainties are the standard deviations. A similar treatment of the results of free surface pressure over basal plane oriented single crystals gave the following expression for the apparent total pressure in the temperature range of 741°–793°K: logP false(normalatmfalse)=false(10.312±0.693false)−false(1.280±0.053false)104/T . Assuming the sublimation reaction Bi2Te3 false(Sfalse)=2 normalBiTe false(normalgfalse)+½Te2 false(normalgfalse) , average third‐law enthalpies and activation enthalpies of sublimation at 298°K were found to be 127.4±1.2 normaland 133.1±1.8 normalkcal/normalmole , respectively. Calculated values of the sublimation coefficient varied from 0.14 at 722°K to 0.39 at 828°K.

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