Interaction between conduction band edge and nitrogen states probed by carrier effective-mass measurements in GaAs1-xNx

The electron effective mass, m(e), has been determined by magnetophotoluminescence in as-grown and hydrogenated GaAs1-xNx samples for a wide range of nitrogen concentrations (from x < 0.01% to x=1.78%). A modified k center dot p model, which takes into account hybridization effects between N cluster states and the conduction band edge, reproduces quantitatively the experimental m(e) values up to x <= 0.6%. Experimental and theoretical evidence is provided for the N complexes responsible for the nonmonotonic and initially puzzling compositional dependence of the electron mass.