ELECTRON AND ATOMIC-FORCE MICROSCOPIC INVESTIGATIONS OF LEAD SELENIDECRYSTALS GROWN UNDER MONOLAYERS

Lead selenide (PbSe) particulate films, composed of highly oriented, e quilateral triangular crystals, have been in situ generated by the exp osure of arachidic-acid- (AA) monolayer-coated aqueous lead nitrate [P b(NO3)2] solutions to hydrogen selenide (H2Se). The AA coated PbSe fil ms, at different stages of their growth, were transferred to solid sub strates and characterized by transmission electron microscopy (TEM), e lectron 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 hexagonall y close-packed AA monolayer. The parallel alignment of the less than o r equal to ($) over bar 110> and less than or equal to 00 $$($) over b ar 1> axes and the perpendicular alignment of the less than or equal t o 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 require ment for the oriented growth of PbSe crystals. (C) 1994 Wiley-Liss, In c.