GaAsN/GaAs and InGaAsN/GaAs T-shaped quantum wires (T-QWRs) grown by metal-organic vapor phase epitaxy have been investigated by low-temperature photoluminescence (LT-PL) and temperature dependent PL to verify their optical properties. The T-QWR structure was clearly observed at the intersection of their familiar quantum wells (QWs), namely QW1 and QW2. LT-PL spectra show the related QWR feature located at the lower energy side of their quantum wells related peaks. It is found that the quantum energy state in the T-QWR structure depends on the quantum energy states in QW1 and QW2. It is interpreted that they act as the second confinement barrier of QWR, which is occurred by the effect of the lateral confinement energy. In our case, the lateral confinement energy larger than 100 meV was observed for all samples. This is expected to be very useful for carrier confinement at higher temperature. PL spectrum of InGaAsN/GaAs T-QWR shows smaller peak-width and higher intense than that of GaAsN/GaAs T-QWRs. It may be explained by the strain compensation from an In atom incorporation, reducing the lattice distortion and improving the alloy fluctuation in the wire region. (C) 2012 Elsevier B.V. All rights reserved.