In this work, the authors present a systematic study on the variation of the structural and the optical properties of GaAsSbN/GaAs single quantum wells (SQWs) as a function of nitrogen concentration. These SQW layers were grown by the solid source molecular beam epitaxial technique. A maximum reduction of 328 meV in the photoluminescence (PL) peak energy of GaAsSbN was observed with respect to the reference GaAsSb QW. 8 K and RT PL peak energies of 0.774 eV (FWHM of similar to 25 meV) and 0.729 eV (FWHM of similar to 67 meV) (FWHM denotes full width at half maximum) corresponding to the emission wavelengths of 1.6 and 1.7 mu m, respectively, have been achieved for a GaAsSbN SQW of N similar to 1.4%. The pronounced S-curve behavior of the PL spectra at low temperatures is a signature of exciton localization, which is found to decrease from 16 to 9 meV with increasing N concentration of 0.9%-2.5%. The diamagnetic shift of 13 meV observed in the magnetophotoluminescence spectra of the nitride sample with N - 1.4% is smaller in comparison to the value of 28 meV in the non-nitride sample, indicative of an enhancement in the electron effective mass in the nitride QWs. Electron effective mass of 0.065m, has been estimated for a SQW with N similar to 1.4% using the band anticrossing model. (c) 2007 American Vacuum Society.