Unveiling the physical properties of group III-nitride ultrawide band gap semiconductors: β-naphthyldiene, graphenyldiene, and β-naphthylene-based monolayers

Abstract

We introduce six new ultrawide band gap semiconductor monolayers based on graphenyldiene (IGPD) and $\beta$-naphthylene (INP) frameworks, incorporating III-nitride compounds (AlN, BN, and GaN). Additionally, we propose a porous structure, naphthyldiene (INPD), which integrates features from both frameworks. The optimized unit cells exhibit distinct symmetries: IGPD-AlN, IGPD-BN, and IGPD-GaN show hexagonal $P\overline{6}m2$ (No. 189) space group, while INP-BN, INP-AlN, and INP-GaN adopt the rectangular $Pmma$ (No. 51) symmetry. The INPD monolayers, which combine the features of both the IGPD and INP structures, stabilize in the orthorhombic $Amm2$ (No. 38) space group. Phonon calculations confirm the absence of imaginary modes, demonstrating dynamical stability, while ab initio molecular dynamics simulations at 300 K indicate thermal robustness, with energy fluctuations below 1 eV/atom. Electronic structure calculations reveal band gaps ranging from 4.15-7.31 eV. Furthermore, all monolayers satisfy the Bohr-Huang stability criterion. Mechanical analysis indicates that INP-based monolayers exhibit the highest Young’s modulus, with INP-BN reaching 240.37 N/m, followed by INP-AlN (130.06 N/m) and INP-GaN (113.67 N/m). These results highlight the potential of the proposed monolayers in rigid and transparent high power electronics and deep ultra-ultraviolet radio frequency electronics applications.