Nonequilibrium electron distributions and high-field electron transport in an Al/sub x/Ga/sub 1-x/As-based p-i-n nanostructure semiconductor-a picosecond Raman probe

Electron transport in an Al/sub x/Ga/sub 1-x/As (x=0.3) based p-i-n nanostructure semiconductor under the application of an electric field has been studied at T=80 K by picosecond transient Raman spectroscopy. Single-particle excitations associated with spin-density fluctuations were used to directly measure electron distribution functions and drift velocities under various electric field intensities. Extremely nonequilibrium electron distributions were observed. Specifically, for an injected carrier density of n/spl cong/1/spl times/10/sup 18/ cm/sup -3/, a drift velocity V/sub d/ as high as 2.5/spl times/10/sup 7/ cm/s was measured for an electric field intensity E=18 kV/cm. These experimental results are in good agreement with Ensemble Monte Carlo calculations.