Both p-type and n-type dilute-nitrogen GaNAs epitaxial layers grown by metal-organic chemical vapor deposition were characterized by deep-level transient spectroscopy (DLTS). For each case, the dominant DLTS signal corresponds to an electron trap having an activation energy of about 0.2-0.3 eV for p-type GaNAs and about 0.3-0.4 eV for n-type GaNAs. In p-type GaNAs, the electron traps fill slowly, as the DLTS signal reaches saturation using zero-bias filling pulses with widths of Is. The electron traps fill quickly in the n-type GaNAs, as the DLTS signal does not typically increase after the shortest fill time of 10 As. The electron-trap densities are calculated using modeling that accounts for the spatial region where traps fill and emit during DLTS measurement. A set of p-type samples with mid-10(16) cm(-3) net acceptors has N content ranging from 0.02% to 1.2%, and the resulting electron-trap concentrations range from 1.4 X 10(17) to 4.3 X 10(17) cm(-1). A set of n-type samples with mid-10(17) cm(-3) doping has N content ranging from 0.011% to 0.45%, and the resulting electron-trap concentrations range from 7.6 X 10(14) to 3.6 X 10(16) cm(-3). Additionally, a set of p-type samples with similar to 0.25% N content has hole concentrations ranging from 4.3 X 10(16) to 1.3 X 10(17) cm(-3), and the resulting electron-trap concentrations increase with acceptor doping ranging from 3.1 X 10(17) to 7.2 X 10(17) cm(-3). A set of n-type samples with similar to 0.25% N content has electron concentrations ranging from 4.5 X 10(16) to 7.8 X 10(17) cm(-3). The resulting electron-trap concentrations also increase with donor concentration from 5.7 X 10(15) to 3.5 X 10(16) cm(-3). The modeling of the Poole-Frenkel effect predicts that the trap may be about 100 meV deeper than implied by the measured activation energies. (c) 2006 American Vacuum Society.