Efficient AlGaN-based laser diodes (LDs) with emission wavelengths between 300nm and 370nm (UVA LDs) have numerous applications in the fields of lithography, 3D printing, curing, chemical sensing, cytometry, atmospheric LIDAR, and more. Lattice mismatches and dislocations are common obstacles that need to be addressed during the construction of UVA LDs. The devices can be formed on either low dislocation density HVPE-grown GaN substrates or AlN templates grown on sapphire substrates. The former method has yet to demonstrate a device with a suitable lifetime, a result of severe device cracking caused by tensile stress between the substrate and AlGaN layers. The latter method is opposed by the large lattice mismatch between the AlN template and the AlGaN active region when the emission wavelength of the LD is around 350~370nm, creating a large number of dislocations. Relieving either of these methods from their device growth drawbacks would enable a new generation of highly efficient, long-lasting laser devices that outpace their gas phase/solid-state counterparts by a wide margin.
Ultraviolet laser diode, Nano-porous AlGaN template, Efficient AlGaN-based laser diodes, UVA LDs, Emission wavelengths between 300nm and 370nm, Lattice mismatches, Dislocations HVPE-grown GaN substrates, AlN templates on sapphire substrates, Device cracking, Tensile stress