InGaNAs single quantum well laser diodes were grown on GaAs substrates using solid-source molecular beam epitaxy with N-2/Ar gas mixtures in an radio-frequency (RF) plasma cell. The structures employ GaNAs barriers which reduce the quantum confinement and extend the room temperature stimulated emission wavelength to 1.36 mum. Test quantum well structures were grown with and without these barriers to demonstrate the significant redshift in emission (similar to36 meV) resulting from the change in potential barrier height. We also demonstrate the temperature dependence of post-deposition rapid thermal annealing, and show that the optimal temperature is near 800 degreesC for both types of test structure. Likewise, the blueshift with annealing is similar in both cases. The broad-area, ridge-waveguide laser diodes exhibit internal quantum efficiencies and internal losses of eta(i) = 53 +/- 7% and alpha(i) = 9.8 +/- 4.0 cm(-1), with a transparency current density of 304 +/- 17 A cm(-2). These results demonstrate the potential of the N-2/Ar RF plasma technique for device-quality MBE layers. Crown Copyright (C) 2002 Published by Elsevier Science Ltd. All rights reserved.