Optical time‐of‐flight investigation of ambipolar carrier transport in GaAlAs using GaAs/GaAlAs double quantum well structures

We propose a new all‐optical time‐of‐flight method which provides transport properties like the average carrier velocity and diffusivity from measurements of the flight duration in semiconductor materials sandwiched between two quantum wells. The method is capable of very high spatial and temporal resolution and is demonstrated by time‐of‐flight experiments in GaAlAs.