OBSERVATION OF PLASMON-OPTIC PHONON COUPLED MODES IN GAAS ALGAAS RESONANT-TUNNELING STRUCTURES VIA ACOUSTIC-PHONON DECAY PRODUCTS/

Using a nanosecond pulse technique to detect acoustic phonon decay pro ducts, we have observed plasmon-optic phonon coupled modes excited by tunneling electrons in the heavily doped collector of a double barrier resonant tunneling structure. From steps observed in the bias voltage dependence of the detected phonon flux we inferred the coupled mode e nergies to be 50 and 30 meV. Both modes decayed predominantly via latt ice rather than electronic processes. Their widths were unexpectedly n arrow, the result we believe of spatial inhomogeneity of collector car rier concentration.