Y. Abramovich et al., PHOTOINDUCED ABSORPTION WITHIN THE VALENCE GAMMA-SUBBAND AND THE CONDUCTION L-SUBBAND MANIFOLDS IN UNDOPED GASB ALSB SUPERLATTICES/, Superlattices and microstructures, 15(4), 1994, pp. 489-493
We report the observation of L-valley conduction intersubband absorpti
on together with Gamma- valence intersubband in optically excited undo
ped, indirect binary-binary short period GaSb/AlSb superlattices. The
transitions were identified by comparing their position and polarizati
on with calculations which take into account both valence and conducti
on subbands. The dependence of the intersubband absorption on the temp
erature, excitation intensity and modulation frequency, indicates that
the photoexcited carriers are trapped with an activation energy of si
milar or equal to 50 mu meV and are long lived (similar or equal to 5
mu sec).