We have investigated the electrical and optical properties of p-i-n junction structures in which undoped GaNAs/GaAs multiple quantum wells (MQWs) were sandwiched by p- and n-doped GaAs layers. The samples were formed on the GaAs (001) substrates by plasma assisted molecular beam epitaxy (RF-MBE) using the modulated N radical beam method. We have prepared several samples for various GaNAs MQW structures. The electroluminescence (EL) measurements showed slightly different spectra to those of photoluminescence (PL) and the EL intensities were almost proportional to the applied currents. The room temperature EL measurement revealed strong electron confinement of GaNAs/GaAs MQW. (c) 2013 Elsevier B.V. All rights reserved.