The electronic structures of III-V-nitride semiconductors, including InGaAsN, GaAsN, and InAsN grown by molecular beam epitaxy, were investigated by high-resolution x-ray photoelectron spectroscopy using synchrotron radiation beam and low energy Ar+ sputtering. The N(1s) core-level photoelectron spectra show a single peak with a binding energy (E-b) similar to 398.0 eV of N-Ga bonding for GaAsN sample. For the InAsN samples, a single N(1s) peak at E-b similar to 397.0 eV of N-In bonding is observed. For the InGaAsN samples, the N(1s) spectra exhibit two peaks with a major component corresponding to N-In bonding, and a minor one to N-Ga bonding. The integrated N(1s) intensity of N-In bonding has a higher value than that of N-Ga bonding, in spite of the lower mole fraction of In for the InGaAsN sample. The data indicate that N has a bonding configuration with In-rich nearest neighbors in the InGaAsN samples. (C) 2004 American Vacuum Society.