Structure of vapor-deposited Ge films as a function of substrate temperature

Abstract

The structure of Ge films grown by thermal evaporation has been studied as a function of the deposition temperature Ts by X-ray diffraction, Raman scattering, and EXAFS (Extended X-ray Absorption Fine Structure) analysis. It is found that there is a temperature range where the material is microscopically heterogeneous and consists of crystallites embedded in an amorphous connective tissue. The dimension and the percentage of the ordered domains are determined, and the nature of the amorphous to polycrystalline transition is thoroughly investigated. The data support the hypothesis of the instability of the diamond structure for small crystallites.ufoff