An approach toward broader emission bands in semipolar InGaN quantum wells on convex lens-shaped GaN microstructures via lower-temperature growth

InGaN quantum wells (QWs) are grown at different temperatures on convex lens-shaped GaN microstructures formed on the ($\overline{1}\overline{1}2\overline{2}$) plane. Microlens QWs grown at different temperatures have centrosymmetric convex lens shapes, and the wavelength spatial distributions within the structures exhibit similar tendencies. However, lowering the growth temperature broadens the wavelength range of room-temperature cathodoluminescence spectra from the microlens QWs as ≈70 nm for ≈700 °C, ≈100 nm for ≈660 °C, and ≈150 nm for ≈650 °C. Peak wavelength profiles of the two orthogonal lines along [$1\overline{1}00$] and [$11\overline{2}\overline{3}$] indicate that the broader emission bands are mainly due to the significant spatial distribution of the emission wavelength along the [$11\overline{2}\overline{3}$] direction. Because the QW thickness variations are nearly the same along [$1\overline{1}00$] and [$11\overline{2}\overline{3}$], the observed difference in the emission wavelength distributions along those directions is attributed to the difference in In incorporation, which is determined by the competition among the growth rate, crystal orientation, and growth temperature. (© 2024 Wiley‐VCH GmbH)