R. Duer et al., PICOSECOND DYNAMICS OF QUANTUM STRUCTURE CARRIERS MEASURED BY TIME-RESOLVED PHOTOINDUCED INTERSUBBAND ABSORPTION, Superlattices and microstructures, 17(1), 1995, pp. 5-9
A novel interband-pump intersubband-probe technique is developed in or
der to study the dynamics of photogenerated carriers and excitons in G
aAs/AlGaAs superlattices by time resolved photoinduced absorption. The
photogenerated population reaches a thermal distribution a few picose
conds after the excitation. The time dependence of the intersubband ab
sorption strength and its time resolved excitation spectra yield a mea
sure for the time it takes for that population to cool first to the la
ttice temperature and then to radiatively decay. The first time is rou
ghly 70-100 ps depending on the excess energy with which the photogene
rated carriers are created. The second is on a sub-nanosecond scale an
d depends linearly on the lattice temperature.