Electronic properties of semiconductor superlattices: numerical study of the dimer effect

The dynamics of electrons in disordered semiconductor superlattices is investigated. A particular interest has been paid to the localization and delocalization behavior of electrons, in various situations including both ordered, disordered superlattices as well as the presence of random dimer. The random dimer effect is shown to have a direct effect on electronic and transport properties of the system. It is suggested a possible experimental observation of the Anderson localization. Typically, the over quoted GaAs/AlxGa_1-xAs superlattice (SL) has been considered. Here the random dimer is introduced into the sample by means that two AlxGa_1-xAs barriers of different Al mole fractions are introduced at random in the SL, with the restriction that one of them appear only in pairs. The present results can be checked experimentally. The main effect is the breakdown of localization and the existence of extended states having high properties of electronic transport. This feature may be conveniently used to develop a basis of new filter like or any other specific purpose electronic devices.