Fabrication and study of porous PbTe layers on silicon substrates

Fabrication of porous PbTe layers on Si substrates using a developed technique based on anodic electrochemical etching of PbTe/CaF2/Si(111) heteroepitaxial structures in a Norr electrolyte with anodizing current density 2-4 mA/cm(2) is reported. The structural and morphological parameters of such layers are investigated with x-ray reflectometry and diffractometry methods and with high-resolution scanning electron microscopy. The influence of anodizing conditions on the parameters of the layers is discussed, as well as the morphological peculiarities of the anodized structures. The presence of cylindrical mesopores with diameter of 7-26 nm inclined at the angle of similar to 35 degrees to the surface normal is shown. The value of the porosity for the near-surface layer of lead telluride films is in the interval of 41-68% and depends on the anodic electrochemical treatment conditions. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim