The authors report on the achievement of narrow ultraviolet emission using GaN/AlGaN quantum wells grown by metal organic vapor phase epitaxy. The origin of the inhomogeneous broadening of the emission is explained by means of micro-photoluminescence and atomic force microscopy measurements. The effect of the well/barrier interface roughness on the linewidth is found to be marginal, while the impact of Al composition fluctuations of the barriers is highly critical. Emission linewidths as small as 5 meV at 10 K are obtained by decreasing the aluminum concentration fluctuations in the AlGaN barrier. (c) 2007 American Institute of Physics.