Carrier confinement and special crystallite dimensions in layered semiconductor colloids

Abstract

Microcrystallites of the layered semiconductor ${\mathrm{PbI}}_{2}$ were prepared in colloidal form and examined by transmission electron microscopy and optical absorption. The crystallites have lateral dimensions grouped around 12, 18, and 29 A\r{} corresponding to close-packed clusters with bulk ${\mathrm{PbI}}_{2}$ symmetry. Blue-shifted absorption features can be explained by carrier confinement in these differently sized crystallites, each a single layer (\ensuremath{\sim}7 A\r{}) thick.