Prediction of new 2D Hf2Br2N2 monolayer as a promising candidate for photovoltaic applications

In the present work, the structural and optoelectronic properties of pristine and strained hexagonal Hf2Br2N2 monolayer have been investigated using the first-principles calculations. The binding energy, phonon dispersion calculations, and molecular dynamics simulations demonstrated that this monolayer has dynamic and thermal stabilities depending. It was revealed that the unstrained Hf2Br2N2 monolayer is semiconducting with an indirect bandgap of 1.809 eV/2.853 eV using PBE/HSE06 methods, which is perfect for powerful light absorption. Besides, the results show that the biaxial strain is an effective tool for adjusting the energy gap where the indirect energy gap under the strain effects ranged within a range of 2.791 eV at −6% to 2.968 eV at 6%. Our results show that the Hf2Br2N2 monolayer has a high electron carrier mobility of 7780.2 cm2/V.s. Furthermore, it was found that the Hf2Br2N2 monolayer has the strongest absorption ranging from IR to UV region of the light spectrum. The outcomes of this work revealed that biaxial strain can be an effective technique for tuning the optoelectronic properties of the Hf2Br2N2 monolayer. Moreover, these results confirm that this monolayer can be suitable for photodetectors and photovoltaics applications.