Near-field thermal radiation of germanium selenide single layer

Recently, the two-dimensional (2D) material germanium selenide (GeSe) was shown to possess extraordinary physicochemical properties as well as great potential for electrical and optical applications, whereas its thermal radiative properties remain elusive. Here, we present a comprehensive study of the near-field thermal radiation (NFTR) of monolayer GeSe by means of fluctuational electrodynamics theory. It is shown that, at a small vacuum gap, such a 2D semiconductor not only supports a giant heat flux that surpasses the black-body limit by four orders of magnitude but is also far ahead of graphene with the same electron density. This extraordinary thermal radiation is attributed to the strong quasi-elliptic surface plasmon polaritons supported by the monolayer GeSe at near-and midinfrared frequency regions. In addition, we show how electron density affects the NFTR of monolayer GeSe, where the effect can be switched from suppression to enhancement by elevating the vacuum gap. Furthermore, we investigate the possibility of using mechanical rotation to modulate the NFTR. We find that, at a lower electron density, the NFTR of the monolayer GeSe could be more effectively modulated through mechanical rotation. Finally, we investigate the interference effect of the dielectric substrate on the NFTR, pointing out the nonmonotonic dependency between its thermal radiation and the dielectric constant of substrate. All in all, in this paper, we provide a fundamental understanding of the NFTR in GeSe single layer and offer guidance for further research and modulation in emerging energy conversion and thermal management.