Modeling of heat removal from low dimensional nanostructures

We have investigated the acoustic phonon radiation pattern due to electron-acoustic phonon interaction in a double barrier quantum well by solving both the kinetic equations for electrons and phonons. A major peculiarity of acoustic phonon emission from low dimensional structures consists in a violation of the conservation law for the transverse to the quantum well phonon wave vector component. This is due to lack of the translational symmetry in this direction. The typical wave vector of an acoustic phonon interacting with electrons is of the order of (n+n´)/spl pi//a, where a is the width of the quantum well and n and n´ are the numbers of the electron subbands before and after scattering. Except for the case of a strongly degenerate electron gas, the in-plane wave vector of acoustic phonons is smaller than the transverse wave vector, therefore the acoustic phonons carry energy primarily in the direction normal to the quantum well.