Field-induced electron transport and phonon dynamics in a GaAs-basedp-i-nnanostructure: A subpicosecond time-resolved Raman probe

Electron transport and phonon dynamics in a GaAs-based $p$-$i$-$n$ nanostructure under the application of an electric field have been studied by time-resolved Raman spectroscopy at $T=80\mathrm{}$ K. The time evolution of electron density, electron distribution, electron drift velocity, and LO-phonon population has been directly measured with subpicosecond time resolution. Our experimental results show that, for a photoexcited electron-hole pair density of $n\cong {10}^{17}$ cm${}^{-3}$, the effects of the drifting of electrons and electron intervalley scattering processes govern electron transport properties as well as the LO-phonon dynamics. All of the experimental results are compared with ensemble Monte Carlo simulations and satisfactory agreement is obtained.