Strain dependent electronic and optical responses of penta-BCN monolayer

•The p-BCN monolayer is predicted to be a structurally, dynamically, and mechanically stable non-magnetic direct bandgap semiconductor.•The strong mechanical and optical anisotropy with optical absorbance up to 1.08 × 105 cm−1 in VR and 7.01 × 105 cm−1 in UV region is detected.•The p-BCN is a potential candidate in nanomechanical and optoelectronic device applications. [Display omitted] We report here, structural, dynamic, and mechanical stability in pentagonal boron carbon nitride (p-BCN) monolayer, a new member of direct bandgap two-dimensional (2D) semiconductor. The identified visible range bandgap with excellent mechanical strength allows it to be a promising candidate material in optoelectronics, nanomechanics, and optomechanical sensors. By employing density functional theory (DFT), we reveal a unique geometrical reconstruction with rigidity in B–N and C–N bond lengths with applied strain. These quasi-sp3 hybridized short and strong covalent bonding and unique geometry support the monolayer to possess extraordinary mechanical response. The desired bandgap is manipulated by loading the biaxial strain. Most importantly, our predictions on p-BCN show excellent optical response such as good static dielectric constant and refractive index, strong optical absorption (up to 1.08 × 105 cm−1 in VR and 7.01 × 105 cm−1 in UV) with small energy loss and reflectance both appearing in visible and ultraviolet regions (UV). The desired optical response along with the blue and red shift is demonstrated by tailoring with tensile and compressive strain. The predicted strong optical anisotropy provides it’s application in polarized photodetection.