Scanning tunneling microscopy of lead selenide monocrystals and epitaxial layers on barium fluoride.

The topography and atomic arrangement on the (100) surface of n- and p-PbSe monocrystals have been studied in air by scanning tunneling microscopy (STM). It was shown that the chemically polished surface is more rough than the freshly cleaved one. The regular patterns of the atomic scale STM images correspond well to the crystallographic positions of atoms on (100) plane. Several types of surface defects were observed. The peculiarities of the registrations of atomic scale STM images of PbSe monocrystals are discussed. STM was also applied to structure analysis of molecular beam epitaxial layers of PbSe on BaF2 substrate. The topography of epitaxial layers and their atomic structure have been visualized. It appeared that with certain substrate temperatures (100) and (111) oriented grains of PbSe are formed.