Heteroepitaxy of PbS on porous silicon

Abstract

Epitaxial PbS films were grown by molecular-beam epitaxy (MBE) on the surface of porous silicon (PS) formed on the silicon substrate of (111) orientation. The uniform PS layers 5μm thick were produced by electrochemical anodic treatment of n+-silicon in HF solution. The structure of both PbS and buffer PS was studied by X-ray diffraction analysis as well as scanning electron microscopy. The PbS layer has been demonstrated to have a columnar structure at the early stages of growth, while a solid structure of the grown layer has been observed with increasing a thickness of the epitaxial layer up to 0.5–1.0μm. PbS epitaxial films grown on the substrates with the 2–5μm thick PS layers of 20–40% porosity were comparable with the films grown on the BaF2 substrates.