Vertical carrier transport in InGaAsP multiple-quantum-well laser structures: effect of p-doping

Carrier transport across p-doped quantum wells (QWs) has been measured by time-resolved photoluminescence for a number of InGaAsP multiple-quantum-well (MQW) laser structures with different structural parameters. The transport times are found to be of the order of tens of picoseconds. This shows that the interwell carrier transport is a limiting factor in high-speed laser modulation schemes. Modeling of the experiments reveals that carrier transport proceeds with a mobility which is carrier density and time dependent. Even at low-carrier densities, the interwell transport is largely limited by the holes. The p-doping of the QW region is found to be ineffective for speeding-up the interwell carrier transport.