The Behavior of the Double Barrier Heterostructure Coherent Phonons Generator

In this paper, for the first time the non-equilibrium Keldysh Green functions are used to study theoretically a device capable of generating ultra-high-frequency coherent sound. The device consists of a double barrier heterostructure (DBH) tailored to allow a resonant phonon emmission, where the electrons are injected into the system via the application of an external potential. Studies concerning the instability phenomenon of electrons and phonons fluxes were analyzed by varying the widths of the barriers. The results show that the instability disappears for a number of barrier layers less than 12 for well widths of 70 layers.