Fe2O3 single crystals:: hydrothermal growth, crystal chemistry and growth morphology

Hematite single crystals have been grown under hydrothermal conditions. The analysis of atomic structures of the {h k i l} faces has been made, and the sequence of the growth rate change has been explained on the basis of that analysis. Optical and AFM study show two main mechanisms of alpha-Fe2O3 growth. They are layer-by-layer growth and island growth. The morphological characteristics of {1 1 2 0} surfaces are given. Large flat terraces with height h 100-150 nm, width d similar to 10000 nm are observed of the face surface. Terraces are composed from the steps (h 15-65, d 100-1200 nm). AFM-images of small steps demonstrate that they consist of globules with rounded or elongated shapes. Typical heights of globules are 0.5-5 nm, and typical lengths are 30-60 nm. These globules are orderly packed on the face, the elongation being along [1 0 1 0] direction. (C) 2003 Elsevier B.V. All rights reserved.