Interface effect on structural and electronic properties of graphdiyne adsorbed on SiO₂ and h-BN substrates: A first-principles study

We use the first-principles calculation method to study the interface effect on the structure and electronic properties of graphdiyne adsorbed on the conventional substrates of rough SiO₂ and flat h-BN. For the SiO₂ substrate, we consider all possible surface terminations, including Si termination with dangling bond, Si terminations with full and partial hydrogenation, and oxygen terminations with dimerization and hydrogenation. We find that graphdiyne can maintain a flat geometry when absorbed on both h-BN and SiO₂ substrates except for the Si termination with partial hydrogenation (Si-H) SiO₂ substrate. A lack of surface corrugation in graphdiyne on the substrates, which may help maintain its electronic band character, is due to the weak Van der Waals interaction between graphdiyne and the substrate. Si-H SiO₂ should be avoided in applications since a covalent type bonding between graphdiyne and SiO₂ will totally vary the band structure of graphdiyne. Interestingly, the oxygen termination with dimerization SiO₂ substrate has spontaneous p-type doping on graphdiyne via interlayer charge transfer even in the absence of extrinsic impurities in the substrate. Our result may provide a stimulus for future experiments to unveil its potential in electronic device applications.