Search

We report a thorough study of the growth of self-assembled GaN/AlN quantum dots (QDs). These QDs were grown on sapphire substrates using the Stranski-Krastanov (SK) growth mode by means of low-pressure metal organic vapor phase epitaxy. The influence of the V/III ratio on the QD height, shape, and density is studied. Emissions above (3.8 eV) and below (2.8 eV) the band gap of GaN are observed for small dots (1.3 nm) and large ones (4.4 nm), respectively. Special emphasis was given to the SK growth mode transition and the parameters influencing the QD formation. The two-dimensional–three-dimensional transition is studied continuously by photoluminescence mapping showing its high sensitivity to the V/III ratio. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]