Field electron emission performance of Janus MoSSe and MoSSe-MWCNTs composite: Corroboration by Hall measurement and DFT simulation

Abstract

Janus MoSSe and its composite with multiwalled carbon nanotubes (MWCNTs) have been synthesized using a facile one pot hydrothermal route. Formation of Janus MoSSe has been confirmed from the X-ray Diffraction, Raman, and X-ray Photoelectron spectroscopic analysis. Furthermore, field electron emission (FEE) behaviour of the as-synthesized Janus MoSSe and MoSSe-MWCNTs composite has been investigated at base pressure of ∼ 1 × 10−8 mbar in a planar diode configuration. Interestingly, the MoSSe-MWCNTs emitter exhibited enhanced FEE characteristics in terms of lower values of turn-on and threshold fields, competency to deliver large emission current density, in contrast to the pristine Janus MoSSe and MWCNTs emitters. An attempt has been made to reveal the underlying physics facilitating improvement in FEE behavior using computational analysis. In this regard, density functional theory (DFT) simulation was carried out to find electronic structure of the as-synthesized emitters. The DFT results indicate charge transfer from C 2p to Mo 4d orbitals, thereby enhancing electrical conductivity and reduction in work function of MoSSe-MWCNTs composite. Moreover, the experimental validation due to Hall measurements undoubtedly revealed noticeable increase in carrier concentration. The observed results clearly exemplify modulation electronic properties of Janus materials thereby highlighting their potential for various applications, including vacuum microelectronic devices.