Energy band splitting phenomenon in intercalated dielectrics
Abstract
It is shown experimentally that during intercalation the donor organic molecules are aligned along the dielectric and semiconductor crystal layers, whereupon the lattice period formed from the organic molecules is greater than or a multiple of the initial lattice period a0 of the hexagonal crystal PbI2. The lattice period a for quinoline and aniline is 4a0, for nonylamine is 5a0, for decylamine is 6a0, and for dimethylcetylamine is 7a0. The appearance of a long-period modulating potential results in splitting of the conduction and valence bands of the initial crystal, where the multiplicity of the splitting equals the multiplicity of the increase in the lattice period. Splitting of the energy bands is established experimentally by means of diffuse reflection optical spectra of PbI2 intercalated by organic molecules. Charge transfer from the organic molecules to the crystal-matrix results in complete filling of the lower subband in the conduction band.