A van der Waals heterostructure of MoS2/MoSi2N4: a first-principles study

Motivated by the successful preparation of MoSi2N4 monolayers in the last year [Y.-L. Hong et al., Science, 2020, 369, 670-674], we investigate the structural, electronic and optical properties of the MoS2/MoSi2N4 heterostructure (HTS). The phonon dispersion and the binding energy calculations refer to the stability of the HTS. The heterostructure has an indirect bandgap of 1.26 (1.84) eV using PBE (HSE06) which is smaller than the corresponding value of MoSi2N4 and MoS2 monolayers. We find that the work function of the MoS2/MoSi2N4 HTS is smaller than the corresponding value of its individual monolayers. The heterostructure structure can enhance the absorption of light spectra not only in the ultraviolet region but also in the visible region as compared to MoSi2N4 and MoS2 monolayers. The refractive index behaviour of the HTS can be described as the cumulative effect which is well described in terms of a combination of the individual effects (the refractive index of MoSi2N4 and MoS2 monolayers).

Automated summary

The study investigates the structural, electronic, and optical properties of the MoS2/MoSi2N4 heterostructure, finding that it has a smaller indirect bandgap and lower work function compared to individual monolayers. The heterostructure can enhance light absorption in both the ultraviolet and visible regions. The refractive index behavior of the HTS is described as a cumulative effect of the individual effects of the MoSi2N4 and MoS2 monolayers.