Electron velocity overshoot in a GaAs-based p - i - n nanostructure semiconductor observed by transient subpicosecond Raman spectroscopy

We report direct measurements of nonequilibrium electron distributions and electron drift velocities in a GaAs-based p-i-n nanostructure semiconductor by using transient subpicosecond Raman spectroscopy. Experimental conditions are such that the velocity overshoot phenomenon dominates the transport properties of the photoexcited carriers. These experimental results are compared with ensemble Monte Carlo calculations.