Phase transition of ultrathin AlN interlayer at AlGaN/GaN interface

摘要

The authors report the wurtizite to zinc-blende phase transition of ultrathin AlN interlayer at the interface of AlGaN/GaN. The shape transformation of the pinhole from hexagon to dodecagon exhibits the structural transition of the interfacial layer, where exists an AlN segregation interlayer. By transmission electron diffraction, the structure of AlN interlayer is determined to be zinc blende. Ab initio simulations demonstrate that the epitaxial strain favors the formation of the high Al segregation and the phase transition.