Modeling of type-II quantum well and interband cascade lasers

Abstract

vertzcal. The electroluminescence (Fig. Ib) shows clearly two peaks at 10.7 p,m and 8.2 pm wavelengths corresponding to the energies of the two transitions (E,+E,) and (E2-El). The full-width-at-half-maximums (FWHM) ofthe two peaks are identical (6 meV). The position of the peaks shifts very little with current since the Stark effect in a single quantum well is only of second order. With suitable cladding layers for optical confinement, this structure lased at the (E,_E,) transition with a threshold of 4.2 kA/cm2 at cryogenic temperature. Figure 3 shows the corresponding optical powercurrent curve and I-V characteristic. It is noteworthy that this is the first intersubband laser between two excited states of the same well. This is made possible by an appropriate choice of the superlattice electron Bragg reflector of the injector, which increases the lifetime of the n = 3 state by suppressing tunneling. The structure of Fig. 2 is a sequence of diagonal @+E,) and vertical (E2-El) transitions. The active region comprises the a thin (22 nm) and a thick (8.8 nm) quantum well separated by a 2.2-nm barrier. This results in a much longer lifetime of the M = 3 state (10 ps) than that of the n = 2 state (1 ps) and in a reduction of the direct recombination from the n = 3 state to the n = 1 state byemission of optical phonon. This structure is very promising candidate for a dual wavelength semiconductor laser with correlated photon emission. The electroluminescence spectrum (Fig. 2b) shows two pronounced peaks one of which exhibits a strong Stark shift with increasing current since it corresponds to the diagonal transition. This work was partially supported by Office of Naval Research (U. S. Park) under Grant NO. N00014-96-C-0288. Adive region