Largely enhanced infrared absorption in a wide InAlAs/InGaAs quantum well and short-period superlattice barrier structure

摘要

We report here a detailed study of intersubband absorption at 10.7 $mu@m between the localized ground state and the global miniband state in an InAlAs/InGaAs multiple quantum well and short-period superlattice (SL) barrier heterostructure. The use of enlarged quantum well and the superlattice reinforced miniband structure has shown a significant enhancement in the net intersubband absorption. An integrated optical absorption strength of I$-A$/ $EQ 19.5 Abs-cm$+$MIN@1$/ was obtained under the Brewster's incident angle at T $EQ 300 K, which is about five times larger than that of the conventional single bound-to-bound transition in the InAlAs/InGaAs quantum well structure.