Electron-Beam-Induced\nNegative Differential Transconductance\nHomojunction Device Based on van der Waals Materials for Functionally\nComplete Ternary Computing

Negative differential transconductance\n(NDT) devices have emerged\nas promising candidates for multivalued logic computing, and particularly\nfor ternary logic systems. To enable computation of any ternary operation,\nit is essential to have a functionally complete set of ternary logic\ngates, which remains unrealized with current NDT technologies, posing\na critical limitation for higher-level circuit design. Additionally,\nNDT devices typically rely on heterojunctions, complicating fabrication\nand impacting reliability due to the introduction of additional materials\nand interfaces. Here, we utilize an electron beam to develop tungsten\ndiselenide (WSe<sub>2</sub>) homojunction NDT devices with W-shaped\ncurrent–voltage (<i>I</i>–<i>V</i>) characteristics. We demonstrate that electron beam enables the\nmanipulation of Se atoms in WSe<sub>2</sub>, facilitating controllable\nand spatially precise tailoring of the WSe<sub>2</sub> work function.\nThe electron-beam treatment applied to a part of the WSe<sub>2</sub> channel induces a lateral homojunction and ultimately results in\nthe W-shaped <i>I</i>–<i>V</i> curves,\nwhich enable both one-input and two-input ternary logic gates. We\npropose and implement a balanced circuit design for two-input ternary\nNAND, AND, NOR, and OR gates, featuring a low device count, full-swing\noperation, and minimized output signal variations. Together with three\ntypes of ternary inverters also designed in this work, they form a\nfunctionally complete set of ternary logic gatesa prerequisite\nfor practical ternary computing. This work addresses a critical gap\nin the development of NDT-based ternary computing by ensuring functional\ncompleteness and highlights the versatility of electron-beam treatment\nas an engineering tool for tailoring the properties of two-dimensional\nvan der Waals materials.