Lattice Polarity Manipulation of Quasi-vdW Epitaxial GaN Films on Graphene Through Interface Atomic Configuration

Quasi van der Waals epitaxy, a pioneering epitaxy of sp(3)-hybridized semiconductor films on sp(2)-hybridized 2D materials, provides a way, in principle, to achieve single-crystal epilayers with preferred atom configurations that are free of substrate. Unfortunately, this has not been experimentally confirmed in the case of the hexagonal semiconductor III-nitride epilayer until now. Here, it is reported that the epitaxy of gallium nitride (GaN) on graphene can tune the atom arrangement (lattice polarity) through manipulation of the interface atomic configuration, where GaN films with gallium and nitrogen polarity are achieved by forming C-O-N-Ga(3) or C-O-Ga-N(3) configurations, respectively, on artificial C-O surface dangling bonds by atomic oxygen pre-irradiation on trilayer graphene. Furthermore, an aluminum nitride buffer/interlayer leads to unique metal polarity due to the formation of an AlON thin layer in a growth environment containing trace amounts of oxygen, which explains the open question of why those reported wurtzite III-nitride films on 2D materials always exhibit metal polarity. The reported atomic modulation through interface manipulation provides an effective model for hexagonal nitride semiconductor layers grown on graphene, which definitely promotes the development of novel semiconductor devices.

Automated summary

This study reports on the epitaxy of gallium nitride on graphene, demonstrating that atom arrangement (lattice polarity) can be tuned through manipulation of interface atomic configuration to achieve GaN films with different polarities. Additionally, the formation of an AlON thin layer in a growth environment with trace amounts of oxygen by using an aluminum nitride buffer/interlayer leads to unique metal polarity, explaining the observed metal polarity in wurtzite III-nitride films on 2D materials. Reported atomic modulation through interface manipulation provides an effective model for the growth of hexagonal nitride semiconductor layers on graphene, promoting the development of novel semiconductor devices.