Strain-Engineering of Band Gaps in Piezoelectric Boron Nitride Nanoribbons

Abstract

Two-dimensional atomic sheets such as graphene and boron nitride monolayers represent a new class of nanostructured materials for a variety of applications. However, the intrinsic electronic structure of graphene and h-BN atomic sheets limits their direct application in electronic devices. By first-principles density functional theory calculations we demonstrate that band gap of zigzag BN nanoribbons can be significantly tuned under uniaxial tensile strain. The unexpected sensitivity of band gap results from reduced orbital hybridization upon elastic strain. Furthermore, sizable dipole moment and piezoelectric effect are found in these ribbons owing to structural asymmetry and hydrogen passivation. This will offer new opportunities to optimize two-dimensional nanoribbons for applications such as electronic, piezoelectric, photovoltaic, and opto-electronic devices.

Mechanics and Mechanically Tunable Band Gap in Single-Layer Hexagonal Boron-Nitride

“…A single value of bending rigidity 0.95 eV in Equation (1) can describe very well the dependence of E BN on tube radii r, regardless of the rollup direction of the h-BN tubes, indicating the isotropic nature of the bending rigidity for single-layer h-BN. We note that the bending rigidity of h-BN tubes was also reported in reference, [18] where the author showed slight difference in the bending rigidity of h-BN in different directions. What we report here for isotropic bending property in h-BN is consistent with the prediction by elasticity theory that trigonal symmetry crystals in 2D have isotropic bending properties.…”

“…[15][16][17] Now it has been revealed that mechanical strains can tune the band gaps of h-BN nanoribbons (h-BNNR). [18] This justifies the course to re-examine h-BN for all the extraordinary properties * Corresponding author. Email: yujie_wei@lnm.imech.ac.cn observed in graphene.…”

“…[51][52][53] For example, it is known that mechanical straining can alter the band gaps of graphene nanoribbons significantly. [51,[54][55][56][57][58][59] Similarly, it has also been shown that straining can change the band gaps for h-BN nanoribbons [15,18] and large area h-BN. [60] We note that in reference, [60] the authors investigated the bandgap as a function of strain to the strain where the bandgap eventually approaches zero.…”

Opto-electrical Behavior of Pb(Zn1/3Nb2/3)O3–Pb0.97La0.03(Zr,Ti)O3 Transparent Ceramics with Varying Defect Structure

“…The 10% tensile stress in zigzag boron nitride nanoribbons was found to reduce the band gap energy value from 3.5 eV to 1.0 eV (Qi et al 2012). Thus, the applied voltage during the I-V measurement may lower the bandgap energy slightly at the þ ve potential (tensile stress) and increased at -ve (compressive stress), which, subsequently, will lead to light interacting charge recombination device similar to P-N junction (Qi et al 2012). The other possible contributions of current may be due to heating through absorbed light, and the interaction of radiation with crystal lattice and generation of electric dipoles (though transmitted light).…”

“…For piezoelectric materials, recently, it has been proposed that the stress can lead to change in local electronic band structure and cause its tilt (Seinfeld and Pandis 2006;Hu et al 2010). The 10% tensile stress in zigzag boron nitride nanoribbons was found to reduce the band gap energy value from 3.5 eV to 1.0 eV (Qi et al 2012). Thus, the applied voltage during the I-V measurement may lower the bandgap energy slightly at the þ ve potential (tensile stress) and increased at -ve (compressive stress), which, subsequently, will lead to light interacting charge recombination device similar to P-N junction (Qi et al 2012).…”