Invited paper: Picosecond dynamics of dense electron-hole plasmas in InGaAsP films

The dynamics of dense electron-hole plasmas in submicron thick films of InGaAsP are studied by time-resolved absorbance and photoluminescence techniques. The plasmas are created by excitation with a 0.5 ps optical pulse, and have initial densities between 5x10²⁰and 1×10¹⁸cm⁻³. At these high initial densities, significant band filling is observed. The plasma cools rapidly within ~1 ps. The plasma density then decays by rapid spatial expansion driven by the Fermi pressure of the plasma, until a density of ~6x10¹⁸cm⁻³is reached. In this initial phase, plasma expansion is much more rapid than Auger recombination. Subsequently, the plasma decays by a combination of Auger and bimolecular radiative recombination. Band gap renormalization and generation of acoustic phonons resonant with the thickness of the thin films are also observed.