Charging Dynamics in Electrically Pumped Quantum Wells

Injection pumping of quantum-well (QW) lasers can lead to charging of the active region due to the different electron and hole masses. To investigate the significance and physical consequences of this effect, the consequences of electrical pumping and the associated charging phenomena are investigated microscopically. The analysis reveals the necessity to include the extended barrier states energetically above the band edge in addition to the quantum-confined well states. It is shown that the barrier-state populations compensate the QW charging. The replenishing of stimulated carrier recombination under CW laser operation causes persistent charge oscillations at the plasma frequency.