Photoluminescence of Hot Electrons and Scattering Processes in Quantum-Well Structures

Abstract

In earlier work we have observed the optical alignment of 2D-electrons in quantum-well structures, which results in the polarization of hot photoluminescence (HPL) [1]. It was emphasized that the peculiarity of the 2D-motion of electrons manifested itself in the strong dependence of the degree of HPL polarization ρ on the energy of the 2D-motion (such a dependence did not exist in the 3D case). Taking into account the quantum confinement of electrons (but not holes) and ignoring the valence band warping, we have obtained an approximate equation which describes the energy dependence of ρ:

$$ \rho = \frac{{{{({{{{E_o}}} \left/ {{{E_1}}} \right.})}^2}}}{{8(1 + {{{{E_o}}} \left/ {{{E_1}}} \right.}) + 2{{({{{{E_o}}} \left/ {{{E_1}}} \right.})}^2}}} $$

((1))

where E_o is the kinetic energy of the 2D-motion (x,y) of electrons at the point of photocreation and E₁ is the confinement energy. In deriving Eq. (1) the z-component of the momentum was put equal to p_z = (2mE₁)^1/2.