SKKU research team led by Prof. Jin Hong PARK successfully developed a technology for negative differential resistance devices and demonstrated a ternary inverter as a multi-valued logic application. Recently, negative differential resistance devices have attracted considerable attention due to their folded current–voltage characteristic which presents multiple threshold voltage values. Because of this remarkable property, studies associated with the negative differential resistance devices have been explored for realizing multi-valued logic applications. This study demonstrated a negative differential resistance device based on a phosphorene/rhenium disulfide (BP/ReS2) heterojunction that is formed by type-III broken-gap band alignment, showing high peak-to-valley current ratio values of 4.2 and 6.9 at room temperature, and 180 K respectively. Also, the carrier transport mechanism of the BP/ReS2 negative differential resistance device is investigated in detail by analyzing the tunneling and diffusion currents at various temperatures with the proposed analytic negative differential resistance device model. Furthermore, they demonstrated a ternary inverter as a multi-valued logic application. This research of a two-dimensional material heterojunction is a step forward towards future multi-valued logic device research. The result of the study was published in Nature Communication on Nov 7th with a thesis titled: “Phosphorene/Rhenium Disulfide Heterojunction-based Negative Differential Resistance Device for Multi-Valued Logic.”