L6-X6 intervalley scattering time and deformation potential for Al0.6Ga0.4As determined by femtosecond time-resolved infrared absorption spectroscopy.

Abstract

Hot electrons in ${\mathrm{Al}}_{0.6}$${\mathrm{Ga}}_{0.4}$As were produced in the ${\mathit{X}}_{6}$ valley from a photoexcited indirect transition by a 585-nm femtosecond pump pulse. The time evolution of the population of electrons in the bottom of the ${\mathit{X}}_{6}$ alley was monitored by a femtosecond infrared probe pulse. The ${\mathit{L}}_{6}$\ensuremath{\rightarrow}${\mathit{X}}_{6}$ intervalley scattering time of \ensuremath{\sim}200 fs and the ${\mathit{L}}_{6}$${\mathit{X}}_{6}$ intervalley deformation potential of \ensuremath{\sim}2.7\ifmmode\times\else\texttimes\fi{}${10}^{8}$ eV/cm were determined from the measured kinetic data.