Tunable Schottky barriers in TaTe2-In2XY ((X≠Y)= S, Se, Te) van der Waals heterostructures via interface engineering

Abstract

We focus on exploring the potential of novel two-dimensional (2D) Janus materials to overcome critical challenges in advanced nanoelectronic devices by achieving Ohmic contact at the metal–semiconductor (MS) interface. The asymmetrical structure with unique electronic properties of these Janus materials, offer promising opportunities to optimize contact resistance and enhance carrier mobility for high-performance nanoelectronic devices. Using a series of calculations based on Density Functional Theory (DFT), electronic properties and contact type (Schottky/Ohmic) at the interface of TaTe${}_2$-In${}_2$XY ((X$\ne$Y)= S, Se, Te) van der Waals heterostructures (vdWHs) are investigated. The mechanical and thermal stabilities of these systems are confirmed via Born criteria, binding energy and ab-initio molecular dynamic (AIMD) simulations, while phonon spectra are used to further verify their dynamical stability. Electronic band structure and density of states show type-III band alignment with the p-type Schottky contact at the interface of TaTe${}_2$-In${}_2$XY ((X$\ne$Y)= S, Se, Te) vdWHs. These calculations are followed by a detailed examination of the strain engineering to modulate height of the Schottky contact and tunneling barrier probability. Interestingly, a compressive strain of 2% switched TaTe${}_2$-In${}_2$STe and TaTe${}_2$-In${}_2$SeTe from Schottky to Ohmic contact, highlighting the tunability of these vdWHs for tailored electronic applications. Electrostatic potential along z-direction, confirm transfer of charge from TaTe${}_2$ to the In${}_2$XY layer in TaTe${}_2$-In${}_2$XY ((X$\ne$Y)= S, Se, Te) vdWHs. Charge density difference and Bader charge analysis, show charge depletion (accumulation) around TaTe${}_2$ (In${}_2$XY) layer, that indicate loses (gain) of electrons in TaTe${}_2$ (In${}_2$XY). Our findings demonstrate the critical role of strain engineering in optimizing contacts resistance along with tunneling barrier (TB) modulation, providing a pathway to understand the mechanisms for designing next-generation nanoelectronic devices.