Effect of Film Thickness on Structural Stability for BAlN and BGaN Alloys: Bond‐Order Interatomic Potential Calculations

Abstract

The effects of film thickness on the relative stability among 5-fold coordinated hexagonal, 4-fold coordinated wurtzite and zinc blende structures in BAlN and BGaN alloys are theoretically investigated based on empirical bond-order potential calculations. It is revealed that the trend of stable structure in BAlN alloys is different from that of BGaN alloys. The film thickness for the stabilization of the hexagonal structure increases with boron composition x for B x Ga 1-x N alloys, while the thickness decreases for B x Al 1-x N alloys. The difference in the stabilization of the hexagonal structure between B x Al 1-x N and B x Ga 1-x N alloys is due to the inhibition of in-plane lattice relaxation in B x Al 1-x N alloys. These results suggest that our approach using the bond-order potential is feasible to investigate the stability of alloy systems with not only tetrahedrally coordinated forms such as the wurtzite and zinc blende structures but also specific forms containing the 5-fold coordinated hexagonal structure. IntroductionTwo-dimensional (2D) atomic layer materials such as graphene, [1] transition metal dichalcogenides, [2] and hexagonal (Hex) structured boron nitride have currently been paid much attention for applications in nanodevices. As a dielectric substrate for electronic devices, 3-fold coordinated Hex BN has attracted much attention in recent years. However, this material is fabricated only in the form of small flakes. [3] There has been a limited amount fabricated in the