Topological insulator materials like HgTe exhibit unique electronic properties at their interfaces and so peculiar attention has to be paid concerning the growth optimization. Molecular beam epitaxy of tensile strained HgTe/CdTe is investigated as a function of the growth temperature. Crystal quality is checked by using high resolution X-rays diffraction. By combining several material characterization techniques such as scanning transmission electronic microscopy, time-of-flight secondary ion mass spectroscopy and X-rays reflectivity, we report sharp interface morphology with nanometer-scale Hg/Cd diffusion lengths. (C) 2015 Elsevier B.V. All rights reserved.