Single-phase Bi0.5Sb1.5Te3 compounds have been prepared by hydrothermal synthesis at 150 degrees C for 24 h using SbCl3, BiCl3 and tellurium powder as precursors. X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) have been applied to analyze the phase distributions, microstructures and grain sizes of the as-grown Bi0.5Sb1.5Te3 products. It is found that the hydrothermally synthesized Bi0.5Sb1.5Te3 nanopowders have a morphology dominated by irregular hexagonal sheets due to the anisotropic growth of the crystals. The Bi0.5Sb1.5Te3 nanosheets are parallelly stacked in certain direction to form sheet-agglomerates attribute to the temperature gradients in the solution. (C) 2011 Published by Elsevier Ltd.