Low temperature Hall measurements on the X1celectrons in GaAs

Hall measurements to 120 K at 50 kbar have been carried out for electrons in the )100), X 1c , satellite valleys in epitaxial and bulk grown GaAs for carrier concentrations in the range 10 14 -10 18 cm -3 . Two distinct impurity levels have been found to be associated with the X 1c minima; estimates of activation energies 0.145+or-0.02 eV and 0.066+or-0.01 eV have been obtained for carrier concentrations near 10 15 cm -3 . The activation energies of these levels decreased with increasing carrier concentration. Theoretical analysis of mobility-temperature curves has shown intervalley scattering to be dominant for purer samples while for the heavily doped bulk grown samples space-charge scattering becomes more important. A best estimate of the (X 1c -X 1c ) deformation potential field, D xx , of 0.8*10 9 eV cm -1 for a deformation potential E 1 of 5.0 eV has been obtained.