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 products, 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 energies to be 50 and 30 meV. Both modes decayed predominantly via lattice rather than electronic processes. Their widths were unexpectedly narrow, the result we believe of spatial inhomogeneity of collector carrier concentration.