Theoretical performance and structure optimization of 3.5-4.5 mu m InGaSb/InGaAlSb multiple-quantum-well lasers

We present a comprehensive theoretical investigation to optimize 3.5-4.5 mu m InGaSb/InGaAlSb quantum-well (QW) lasers grown on ternary InGaSb substrat es. We use an eight-band k.P Hamiltonian to calculate the Auger recombinati on and optical absorption coefficients in the active region, as well as the gain and threshold characteristics. The dominant Auger process involves ho le excitation from the QW to unbound valence states. For structure optimiza tion we varied the Ga content in the substrate and QW barrier layers. The o ptimized structure was obtained by maximizing the strain in the QWs, despit e the Auger coefficient also increasing with strain. It is, therefore, demo nstrated that the main aim for midinfrared laser optimization can be minimi zation of the threshold carrier density rather than reduction of the Auger coefficient. (C) 2001 American Institute of Physics.