Observation of large electron drift velocities in InN by ultrafast Raman spectroscopy

Electron transport in an InN film grown on GaN has been studied by transient Raman spectroscopy at $T=300\mathrm{K}$ . Our experimental results demonstrate that under the subpicosecond laser excitation and probing, electron drift velocity of carriers in the $\Gamma$ valley can exceed its steady-state value by as much as 40%. Electron velocities have been found to cut off at around $2\times {10}^8\mathrm{cm}∕\mathrm{s}$ , significantly larger than those observed for other III-V semiconductors, such as GaAs and InP. These experimental results have been compared with ensemble Monte Carlo simulations and good agreement has been obtained.