Exploring the electronic and optical properties of g-C3N4/HfN2 Nanoheterojunctions: A novel semiconductor for optoelectronic applications

In this study, we report a novel van der Waals heterojunction composed of g-C₃N₄ and HfN₂, hypothesizing that the combination of these materials into a nanoheterojunction can yield synergistic enhancements in charge carrier dynamics, band alignment, and optoelectronic behaviour. Using hybrid-functional DFT (HSE06) and DFPT calculations, this study systematically explores the electronic, optical, and phonon properties of the g-C₃N₄/HfN₂ nanoheterostructure. The results demonstrate that the heterojunction exhibits a stable structure with a desirable indirect bandgap of 1.697 eV, high visible-light absorption, favourable band edge positions for photocatalytic water splitting, and reduced electron-hole recombination as evidenced by charge density difference and DOS analyses. Phonon spectrum analysis confirms dynamic stability, while the optical spectra indicate isotropic absorption—an essential feature for practical device integration.