Fingerprints of spatial charge transfer in quantum cascade lasers

R. Nelander, A. Wacker, M. F. Pereira, D. G. Revin, M. R. Soulby, L. R. Wilson, J. W. Cockburn, A. B. Krysa, J. S. Roberts, R. J. Airey

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


We show that mid-infrared transmission spectroscopy of a quantum cascade laser provides clear-cut information on changes in charge location at different bias. Theoretical simulations of the evolution of the gain/absorption spectrum for a λ∼7.4 μm InGaAs/AlInAs/InP quantum cascade laser have been compared with the experimental findings. Transfer of electrons between the ground states in the active region and the states in the injector goes hand in hand with a decrease of discrete intersubband absorption peaks and an increase of broad, high-energy absorption toward the continuum delocalized states above the barriers.

Original languageBritish English
Article number113104
JournalJournal of Applied Physics
Issue number11
StatePublished - 2007


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