Researchers at the Department of Electronic Systems Engineering, Indian Institute of Science published a new paper conserning the simulations of asymmetric junctions in Metallic-Semiconducting-Metallic (MSM) Heterophase MoS2 using ATK [1].
The energy barrier height difference at two β- and β*- interfaces of a MoS2 device has been studied. The further studies on the effect of semiconductor doping on the transmission show that, irrespective of the doping concentration, these hetero-phase structures exhibit asymmetric barrier heights. The findings show some interesting features of this very hot material in circuit component design.
In this article, the ATK optimization results of the Metal-Semiconductor (M-S) and Semiconductor-Metal (S-M) interfaces have been shown to be in good agreement with the experiment. The Density Functional Theory (DFT) and Non-equilibrium Green’s function (NEGF) formalism have been applied for the electronic and transport properties.
Two devices with M-S and S-M interfaces have been constructed and optimized in the VNL user interface, an easy-to-operate tool for interface optimization. The calculated effective electron barrier height at the two interefaces shows a 0.2V difference, despite the doping concentration.
Plotting out the local density of states to show the band-alignment is a powerful tool for learning about device transport properties. The image is direct and the physics is clear. The integrated function of Projected Local Density of States enables the users to access high quality plots without requiring hard coding and a tedious parameter tuning process. A tutorial related to LDOS plotting can be found here.
References:
[1] D. Saha, S. Mahapatra, "Asymmetric Junctions in Metallic-Semiconducting-Metallic Heterophase MoS₂", IEEE Transactions on Electron Devices, vol.PP, no.99, pp.1 (2017)