1：Experimental Design and Method Selection:

The study involves theoretical calculations using first-principles calculations based on density functional theory to examine the formation mechanism of AlN on graphene. An AlN composite nucleation layer is inserted between graphene and GaN, grown by metal organic chemical vapor deposition (MOCVD) using a time-distributed and constant-pressure growth method.

2：Sample Selection and Data Sources:

Large-area graphene was synthesized via CVD on Cu foils and transferred to sapphire substrates. GaN and LED structures were grown on the graphene/sapphire substrates.

3：List of Experimental Equipment and Materials:

Equipment includes MOCVD for GaN growth, ellipsometer for thickness measurement, SEM, AFM, Raman spectroscopy, and PL measurements for characterization.

4：Experimental Procedures and Operational Workflow:

The growth process of AlN was divided into three stages with varying V/III ratios to manufacture defects, promote horizontal merging of nucleation islands, and accelerate the growth rate of the AlN film. GaN and LED structures were then grown on the AlN/graphene composite substrate.

5：Data Analysis Methods:

Characterization techniques included SEM, AFM, Raman spectroscopy, and PL measurements to analyze the quality and properties of the grown layers and LED structures.