Crystallization and melting in metal-semiconductor multilayers.

The amorphous-to-microcrystalline phase transition of Ge in Pb/Ge multilayer geometry has been investigated as a function of layer thicknesses with the use of high-temperature x-ray diffraction techniques. During crystallization, the modulation structure is destroyed and the Pb texture improves. In addition, the crystallization temperature decreases with decreasing amorphous Ge thickness and increases with decreasing thickness of the metallic component. The results imply that the crystallization is interfacially initiated and possibly affected by electron transfer. A study of two-dimensional melting for Pb in this system was attempted unsuccessfully because the layered structure was destroyed by the crystallization that occurs substantially below the melting temperature.