SKM 2023 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 34: 2D Materials V (joint session HL/CPP)
HL 34.1: Vortrag
Donnerstag, 30. März 2023, 09:30–09:45, POT 81
Negative differential resistance with ultra-high peak-to-valley current ratio in tunnel diodes based on two-dimensional cold metals — •Ersoy Sasioglu and Ingrid Mertig — Martin-Luther-Universität Halle-Wittenberg, Institut für Physik, 06120 Halle (Saale)
The negative differential resistance (NDR) effect is of great interest for future memory and logic circuit applications. We propose a novel semiconductor-free NDR tunnel diode concept with ultra-high peak-to-valley current ratio (PVCR) [1]. Our proposed NDR diode consists of two cold metal electrodes separated by a thin insulating tunnel barrier. The NDR effect stems from the unique electronic band structure of the cold metal electrodes, i.e., the width of the isolated metallic bands around the Fermi level as well as the energy gaps separating higher- and lower-lying bands determine the current-voltage characteristics and PVCR value of the tunnel diode. By proper choice of the cold metal electrodes either Λ-type or N-type NDR effect can be obtained. We employ the nonequilibrium Green’s function method combined with density functional theory to demonstrate the NDR characteristics of the proposed diode based on two-dimensional NbS2/h-BN/NbS2 vertical and AlI2/MgI2/AlI2 planar heterojunctions. For the lateral tunnel diode, we obtain a Λ-type NDR effect with an ultra-high PVCR value of 1016 at room temperature, while the vertical tunnel diode exhibits a conventional N-type NDR effect with a smaller PVCR value of about 104. The proposed concept provides a semiconductor-free solution for NDR devices to achieve desired I-V characteristics.
[1] Ersoy Şaşioğlu and Ingrid Mertig, arXiv:2207.02593 (2022).