Hysteresis Effect in Two-Dimensional Bi₂Te₃ Nanoplate Field-Effect Transistors

Recently, field-effect transistors (FETs) based on two-dimensional (2D) Bi₂Te₃ nanoplates have attracted much attention due to their great potential for fabricating high-performance electronic devices. However, the gating property measurement of the Bi₂Te₃ nanoplate FETs exhibits hysteretic behavior in an ambient environment, which degrades not only their electrical properties, but also their device performance. This work presents a systematical study on the origins of this hysteresis effect in 2D Bi₂Te₃ FETs and explores effective approaches to minimize and eliminate this hysteresis effect. The hysteresis effect in 2D Bi₂Te₃ nanoplate FETs can be attributed to the charge trap states caused by the water molecules adsorbed on the nanoplate surface. To minimize and eliminate this hysteresis, poly(methyl methacrylate) layer is applied to passivate the 2D Bi₂Te₃ FETs, which leads to almost hysteresis-free gating property and thus improves the carrier mobility and device performance. These results indicate that the surface/interface trap states of nanostructures can significantly influence their electrical properties and thus device performance, and as a result, surface passivation is required to minimize the influence of the surface/interface trap states and achieve high device performance.