We report an experimental study of the optical properties of a GaAs/AlAs short period superlattice (SPSL) by photoluminescence and time-resolved two-pulse correlation experiments. Our SPSL is designed in such a way that the lowest confined Γ state in the GaAs is only slight (30-50 meV) above the X states in the AlAs. Therefore the Γ→X transfer due to LO-phonon emission or interface scattering is prohibited by X-band filling at high excitation densities and small excess energies, which allows us to measure a Γ→X transfer time induced by LO-phonon absorption of 20 ps. By adjusting the laser energy, excitation density, and temperature we are able to transform the emission spectrum of the SPSL completely from a type-I into a type-II transition.
|Number of pages||3|
|Journal||Applied Physics Letters|
|Publication status||Published - 1 Dec 1993|