The acoustic phonon radiation patterns and acoustic phonon spectra due
to electron - acoustic phonon interaction in double barrier quantum w
ell have been investigated by solving both the kinetic equations for e
lectrons and phonons, The acoustic phonon radiation patterns have stro
ngly pronounced maximum in the directions close to the perpendicular t
o the quantum well direction. The radiation pattern anisotropy is expl
ained in terms of possible electron transitions, nonequilibrium electr
on distribution function, and the Hamiltonian of electron-phonon inter
actions.