Graphene-induced crystal-healing of AlN film by thermal annealing for deep ultraviolet light-emitting diodes

Abstract

We achieve stress-free AlN films with low dislocation density by employing Graphene (Gr)-induced crystal-healing via high-temperature annealing (HTA). The N2 plasma-treated Gr effectively facilitates the formation of high-density and small-size AlN grains during the initial quasi-van der Waals epitaxial growth. Thus, it is easier to rotate the inhomogeneous crystal orientation for subsequent AlN epilayers during the HTA process, greatly improving the recrystallization efficiency of AlN. Due to the improved AlN quality, the 283-nm deep ultraviolet light-emitting diode (DUV-LED) on the HT-annealed AlN with Gr shows a significant increase in light output power of 2.3 times at an injection current of 20 mA compared to its counterpart on bare sapphire. This research broadens the applications of Gr in assisting group-III nitride epitaxy and provides a useful strategy for the manufacture of high-quality AlN and high-performance DUV-LEDs.