We report on the advances in quality and uniformity of GaN layers and (Al,Ga)N/GaN quantum wells grown by molecular beam epitaxy using a nitrogen plasma source. The first purpose of this work is to highlight that radio frequency plasma cell is a well-proven nitrogen source to achieve, on 2 inch wafers, III-nitrides heterostructures with both crystalline quality and optical properties consistent with the state of the art. Preliminary studies demonstrate consistently uniform properties in terms of both barrier composition and photoluminescence energy peaks across the wafer. (C) 2008 Published by Elsevier B.V.