Designing β-BeO-type boron nitride nanoribbons for visible-range optoelectronic applications

초록

Conventional two-dimensional (2D) hexagonal boron nitride (h-BN) is a valuable material, yet its wide bandgap restricts visible-light applications, emphasizing the need for alternative phases with a narrower bandgap. In this density functional theory (DFT) based work, we report novel beta-BeO-type BN nanoribbons with n-stacking (n = 1-4) exhibiting thickness-dependent narrow bandgaps falling in the visible range. These nanoribbons are modeled by stacking unit cells of beta-BeO-type BN, a phase derived from wurtzite(w) BN via a pressure-induced transition at similar to 15 GPa. The lack of imaginary frequencies in the phonon band structures of these nanoribbons has validated their dynamic stability. We calculated the band structures to investigate their electronic properties, which revealed that the beta-BeO-type BN nanoribbons exhibit indirect band gaps. The bandgap increases nearly linearly with nanoribbon thickness from 1.68 eV at 2.86 & Aring; to 2.05 eV (7.25 & Aring;), 2.24 eV (11.64 & Aring;), and 2.46 eV (15.67 & Aring;). The designed BN nanoribbons demonstrate strong absorption (similar to 10(4) cm(-1) in visible and similar to 10(6) cm(-1) ultraviolet ranges), and favorable reflectivity and refractive indices. Our results suggest that beta-BeO-type BN nanoribbons can be used for visible-range optoelectronics and energy harvesting applications.

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