Flexible High-Temperature MoS₂ Field-Effect Transistors and Logic Gates.

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) MoS₂ have advantages of superb flexibility, atomic scale, and ultralow power consumption. However, MoS₂ cannot survive at high temperature and drastically degrades above 200 °C. Here, we report MoS₂ 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 MoS₂ devices ever reported, which provides us an opportunity to explore the electrical properties and working mechanism of MoS₂ devices at high temperature. Unlike the relatively low-temperature situation, the on/off ratio and subthreshold swing of MoS₂ 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.