Density of states for dilute nitride systems: calculation of lifetime broadening

Abstract

We present calculations for the band structure of bulk and confined quantum well andquantum wire GaInNAs structures. To treat this non-randomly alloyed material system wefollow previous approaches in using an Anderson impurity model where the nitrogenlocalized states interact with the GaInAs conduction band states. We solve this modelusing Matsubara Green’s functions and the associated self-energies which produce acomplex band structure where both the real and imaginary components depend on theconcentration of nitrogen. In particular this approach gives a definite nitrogen dependentlifetime broadening and is different from previous work in that no artificial inputparameters are used. The density of states of the conduction band, derived from thesefunctions, is strongly altered by interaction with the nitrogen states. The density of statesis required for further optical and transport investigations involving this system.