Influence of Al-concentration on the current density in GaAs/AlGaAs generalized Thue-Morse superlattices.

The influence of Al concentration on the current density in GaAs-AlGaAs heterostructure is studied for two different classes of the Generalized Thue-Morse superlattice (GTS): (i) width-barrier GTS and (ii) height-barrier GTS. The occurrence of resonances in the transmission is found to be highly dependent on the Al concentration as well as on the degree of quasi-periodicity of the system. Interesting features are noted for the current density profile with the increase in the Al content for the width-barrier case. The use of the height-barrier GTS with small Al content could be suggested to achieve the negative differential conducting regimes at comparatively low applied bias. The effects of the applied field as well as of the quasi-periodicity on the carrier localization are also studied. [ABSTRACT FROM AUTHOR]