Electron and atomic force microscopic investigations of lead selenide crystals grown under monolayers

Lead selenide (PbSe) particulate films, composed of highly oriented, equilateral triangular crystals, have been in situ generated by the exposure of arachidic-acid- (AA) monolayer-coated aqueous lead nitrate [Pb(NO32] solutions to hydrogen selenide (H2Se). The AA coated PbSe films, at different stages of their growth, were transferred to solid substrates and characterized by transmission electron microscopy (TEM), electron diffraction, and atomic force microscopy (AFM). The epitaxial growth of PbSe crystals has been rationalized in terms of matching the [111] plane of crystalline PbSe and the (100) plane of the hexagonally close-packed AA monolayer. The parallel alignment of the < or = 110 > and < or = 001 > axes and the perpendicular alignment of the < or = 110 > axis to the monolayer have been suggested to be responsible for the observed formation of rod-like PbSe particles. The presence of a negatively charged monolayer has been found to be an essential requirement for the oriented growth of PbSe crystals.