PHONON EMISSION IN RESONANT-TUNNELING STRUCTURES

We have studied the generation of acoustic phonons in GaAs/AlGaAs doub le barrier resonant tunnelling structures using fast pulses. The TA ph onons arose primarily from decay and down-conversion of cascades of pl asmon-phonon coupled modes, whilst LA phonons were emitted directly by the heated Fermi gas in the collector, Emission was asymmetric with r espect to direction of carrier tunnelling due to enhanced mode convers ion. Intervalley phonon emission could be identified through the aniso tropy of the down-conversion products.