T. Dekorsy et al., INVESTIGATION OF FIELD, CARRIER, AND COHERENT PHONON DYNAMICS IN LOW-TEMPERATURE-GROWN GAAS, Applied physics letters, 63(21), 1993, pp. 2899-2901
We compare the dynamics of electric field, transport, and coherent pho
nons in as-grown and annealed low-temperature (LT) GaAs by an electro-
optic technique on a subpicosecond time scale. The buildup and decay o
f space-charge fields associated with the photo-Dember effect are inve
stigated. The recombination dynamics of trapped carriers is monitored
via the ps decay of the electro-optic signal. Differences in annealed
and as-grown LT GaAs are related to the different microscopic form of
excess arsenic and point defect density. In the coherent phonon signal
a large red shift of the LO phonon and an additional local vibration
below the LO phonon provides information on structural defects in as-g
rown LT GaAs.