Flexible High-Temperature MoS<sub>2</sub> Field-Effect Transistors and Logic Gates
Yixuan Zou, Peng Li, Caizhen Su, Jiawen Yan, Haojie Zhao, Zekun Zhang, Zheng You
Abstract
High-temperature-resistant integrated circuits with excellent flexibility, a high integration level (nanoscale transistors), and low power consumption are highly desired in many fields, including aerospace. Compared with conventional SiC high-temperature transistors, transistors based on two-dimensional (2D) MoS 2 have advantages of superb flexibility, atomic scale, and ultralow power consumption. However, MoS 2 cannot survive at high temperature and drastically degrades above 200 °C. Here, we report MoS 2 field-effect transistors (FETs) with top/bottom hexagonal boron nitride (h-BN) encapsulation and graphene electrodes. With the protection of the h-BN/h-BN structure, the devices can survive at much higher temperature (≥500 °C in air) than those of the MoS 2 devices ever reported, which provides us an opportunity to explore the electrical properties and working mechanism of MoS 2 devices at high temperature. Unlike the relatively low-temperature situation, the on/off ratio and subthreshold swing of MoS 2 FETs show drastic variation at elevated temperature due to the injection of thermal emission carriers. Compared with metal electrode, devices with a graphene electrode demonstrate superior performance at high temperature (∼1-order-larger current on/off ratio, 3–7 times smaller subthreshold swing, and 5–9 times smaller threshold voltage shift). We further realize that the flexible CMOS NOT gate based on the above technique, and demonstrate logic computing at 550 °C. This work may stimulate the fundamental research of properties of 2D materials at high temperature, and also creates conditions for next-generation flexible harsh-environment-resistant integrated circuits.