Plasticity induced texture development in thick polycrystalline CdTe: Experiments and modeling

Abstract

The local and average texture of thick polycrystalline CdTe films is determined before, upon, and after the coalescence of the initially isolated islands, using electron backscattered diffraction and x-ray powder diffraction. The coalescence and postcoalescence processes lead to a preferential texturation, initially along the ⟨531⟩ and ⟨100⟩ crystallographic directions and then along the ⟨110⟩ preferred orientation. The selection of grain orientation during the film growth is found to be driven by strain energy minimization. A model for the microyield stress is developed when plasticity is confined to each elemental grain and accounts for the ⟨531⟩ and ⟨100⟩ preferred orientations. On the contrary, when plastic deformation can propagate from one grain to its neighbors, the Hall–Petch model applies and leads to the ⟨110⟩ preferred orientation. Furthermore, at the end of growth, the stronger ⟨111⟩ preferred orientation is observed and arises because of kinetic limitations.