TRANSPORT MECHANISM OF X-BAND ELECTRONS IN ALAS ELECTRODE THROUGH GAAS ALAS/GAAS STRUCTURE BY VARYING GAAS WELL THICKNESS/

The transport of X band electrons through AlAs/GaAs/AlAs/GaAs/AlAs str ucture with various GaAs well thickness is investigated. The resonant tunneling of X band electrons through X band double barrier is only ob served when the GaAs well thickness becomes smaller than 3 nm. For thi cker GaAs, the single tunneling peak is due to X band electrons tunnel ing through the GAMMA band confined states in the GaAs well. Its longi tudinal optical phonon replica is also observed at temperature below 8 0 K, but disappears at higher temperature. This replica is due to the scattering of electrons from X band of AlAs electrode to the GAMMA ban d of GaAs in order to satisfy the momentum conservation.