Carrier escape time in quantum well lasers: dependence on injection level, doping concentration, and temperature

The transport of carriers along the confinement region, the carrier capture into and the carrier escape out of quantum wells (QWs) are very important processes to be taken into account in order to properly understand the DC and high-frequency properties of QW lasers. In order to obtain information about the carrier dynamics, we have previously performed high frequency impedance measurements for GaAs-based lasers with different geometries, barrier heights and doping concentrations. We have experimentally observed an increase of the escape time constant (τ_esc) with both the p-doping concentration and nominal barrier height, as well as an exponential dependence of τ_esc on the inverse temperature. In this work we present a simple model for the carrier capture and escape processes. It assumes energy conservation in the 3D-2D carrier transitions and considers Fermi-Dirac statistics for the confined carriers