Y. Abramovich et al., INTERSUBBAND L-VALLEY AND HEAVY-HOLE TRANSITIONS IN UNDOPED GASB ALSBSUPERLATTICES/, Physical review. B, Condensed matter, 50(12), 1994, pp. 8922-8925
We report the observation of L-valley-conduction intersubband absorpti
on concurrent with Gamma-valence intersubband absorption in optically
excited undoped binary-binary short-period GaSb/AlSb superlattices. Un
der above-band-gap optical excitation, electrons in these structures o
ccupy the lowest-energy L-valley subband, while holes occupy the highe
st-energy Gamma subband. Due to the separation in k space, these popul
ations have long lifetimes, which enables the observation of photoindu
ced intersubband absorption. Due to the symmetry of the L valleys, the
ir contribution to the intersubband absorption is observed for bath s-
and p-polarized infrared light, in agreement with theoretical predict
ions.