Cathodoluminescence study of deep ultraviolet quantum wells grown on maskless laterally epitaxial overgrown $AlGaN$

We have investigated the cathodoluminescence properties of deep UV quantum wells with an emission wavelength of $287nm$ grown on maskless lateral epitaxial overgrown $Al0.96Ga0.04N$⁠. $AlN$ was grown on sapphire via metalorganic chemical vapor deposition. Parallel, periodic trenches were etched in the $AlN$ and $Al0.96Ga0.04N$ was regrown laterally from the unetched mesas. $Al0.42Ga0.58N∕Al0.36Ga0.64N$ quantum wells were then grown on the uncoalesced stripes. Cathodoluminescence was performed on both the laterally overgrown “wings” and unetched “seed” material. Emission from quantum wells located above the wing region was observed to be more intense than emission above the seed region. Depth dependent cathodoluminescence showed that deep level recombination at $3.58eV(346nm)$⁠, $2.77eV(448nm)$⁠, and $2.14eV(579nm)$ was present throughout the n-type $Al0.45Ga0.55N$ and the laterally overgrown unintentionally doped $Al0.96Ga0.04N$⁠.