We report a slow rise of luminescence in GaAs following photoexcitation by 0.3 ps dye laser near 6000 Å. We show that both the near bandgap luminescence (at 1.44 eV) and the integrated luminescence take nearly 10 ps to reach their maximum value. We show that the primary cause of this slow rise is the slow return of electrons from the L to the r valley. By fitting our data with an ensemble Monte Carlo calculation, we determine the T-L deformation potential to be (6.5±1.5) x108 eV/cm. We show that the electrons returning to the I' valley act as a source of heating for the photoexcited plasma. We further show the importance of electron-electron scattering and inadequacy of a simple phonon cascade model, even at a density as low as 5x 10 16cm-3.
"Intervalley Scattering In GaAs", Proc. SPIE 0942, Ultrafast Laser Probe Phenomena in Bulk and Microstructure Semiconductors II, (22 August 1988); doi: 10.1117/12.947196; https://doi.org/10.1117/12.947196