ANALYSIS OF THE CAPABILITY OF HREM APPLIED TO QUANTUM HETEROSTRUCTURES

This work analyzes the possibilities offered by HREM for the observati on of quantum heterostructures. Multilayers of Cu/Pd, Fe/Ag and Ag/Si are constructed by using a molecular dynamics simulation method and th e configuration of the electronic charge at the interfaces is obtained from a Hartree-Fock calculation of the type extended Debye-Hueckel ap proximation. The HREM image of the multilayers is calculated by using a standard dynamical diffraction method. MD simulations show that in a ll cases good epitaxis can be achieved. However the interfacial region s have a complex structural and electronic configuration which is sign ificantly different from the bulk reference state. As these regions sp an few monolayers across their observation is extremely critical. The HREM image of the films is clear. The interfaces and defective epitaxi al growth can be observed. An interesting possibility for future devel opments appears to be offered by the availability of the interfacial p otential obtained from the HREM image intensity.