Hexagonal GaN microdisk with wurtzite/zinc-blende GaN crystal phase nano-heterostructures and high quality zinc-blende GaN crystal layer

摘要

We revealed that a hexagonal GaN microdisk exhibiting lasing action at a wavelength of approximately 390 nm has peculiar crystal structures consisting of wurtzite (WZ)/zinc-blende (ZB) GaN crystal phase nano-heterostructures and a high-quality ZB GaN crystal layer. Upon transmission electron microscopy measurement, 5-20 monolayer ZB GaN nanocrystals were observed in the WZ GaN crystals in the microdisk, and approximately 250-nm-thick ZB crystals with no dislocations were observed in the upper part of the microdisk. The result indcates that the optical gain of the lasing action at a wavelength of approximately 390 nm is based on ZB GaN crystals.