Current-induced heating in quantum well and quantum wire intersubband emitter structures

We discuss the influence of current-induced heating on the current-voltage ( I - V ) characteristics and the spectral behavior in quantum well and quantum wire intersubband emitter structures. A conventional quantum cascade laser structure in the Al Ga As ∕ Ga As material system with undoped cladding layers and an undoped active region is examined. This heterostructure serves as a first growth step for quantum wire intersubband emitters fabricated by the cleaved-edge overgrowth technique. We discuss the influence of electrons supplied by a remote δ -silicon doping. Duty-cycle dependent measurements on the quantum wire structures confirm the influence of current-induced heating on the I - V characteristics as well as on the emission spectra.