Here’s a couple:
https://www.researchgate.net/profile/Marco_Fanciulli/publication/224426167_Epitaxial_growth_of_zinc_...
https://www.sciencedirect.com/science/article/pii/S0022024800008538
https://techxplore.com/news/2018-08-fujitsu-triples-output-power-gallium-nitride.html
One thing that is difficult, and I have experience with series 2 and 6 elements to make CdSe-based nanocrystals with ZnS shells, is how to deal with crystal lattice mismatch; some elements’ bond lengths just don’t align well in order to interface optimally. Typically, one had to dope in some intermediary element to "fill" the gaps created by the lattice mismatch. Looks like there’s a similar challenge/constraint in fabricating thin layer GaN onto SiC wafers. This is why, IMO, we haven’t seen the industrial "breakthrough," yet. Ideally, one would want pure GaN crystals in the form similar to that achieved with SiC in order to make large enough wafers.
https://www.researchgate.net/profile/Marco_Fanciulli/publication/224426167_Epitaxial_growth_of_zinc_...
https://www.sciencedirect.com/science/article/pii/S0022024800008538
https://techxplore.com/news/2018-08-fujitsu-triples-output-power-gallium-nitride.html
One thing that is difficult, and I have experience with series 2 and 6 elements to make CdSe-based nanocrystals with ZnS shells, is how to deal with crystal lattice mismatch; some elements’ bond lengths just don’t align well in order to interface optimally. Typically, one had to dope in some intermediary element to "fill" the gaps created by the lattice mismatch. Looks like there’s a similar challenge/constraint in fabricating thin layer GaN onto SiC wafers. This is why, IMO, we haven’t seen the industrial "breakthrough," yet. Ideally, one would want pure GaN crystals in the form similar to that achieved with SiC in order to make large enough wafers.