Effect of nitrogen on the temperature dependence of the energy gap in In_xGa_1-xAs_1-yN_y/GaAs single quantum wells

The electronic properties of In_xGa_1-xAs_1-yN_y/GaAs single quantum wells have been investigated by photoluminescence and photoreflectance spectroscopy as a function of temperature. The introduction of nitrogen leads to a sizable slow down in the redshift of the ground state recombination energy with temperature. We explain the observed effects in terms of an anticrossing between states of the conduction band (CB) edge and a N-induced localized level resonant with the CB. The extent of this anticrossing, described by the matrix element V_MN, is derived from the temperature dependence of the exciton recombination energy in a wide compositional range. The measured functional dependence of V_MN on nitrogen concentration is compared with results reported in the literature.