Study of the morphological growth features and optical characteristics of multilayer porous silicon samples grown on $n$-type substrates with an epitaxially deposited $p^+$-layer

This study is concerned with the growth features of multilayer porous silicon with layers of different porosity, obtained by electrochemical etching on an $n$-type single-crystal silicon (111) wafer with a $p^+$-layer epitaxially deposited onto the surface. The possibility of obtaining a multilayer system of ordered pores of various sizes within a single technological cycle is demonstrated. The differences in the optical characteristics of separate layers of the grown structure are shown.