Artificially created interfacial states enabled van der Waals heterostructure memory device

Two-dimensional (2D) interface plays a predominate role in determining the performance of a device that is configured as a van der Waals heterostructure (vdWH). Intensive efforts have been devoted to suppressing the emergence of interfacial states during vdWH stacking process, which facilitates the charge interaction and transfer between the heterostructure layers. However, the effective generation and modulation of the vdWH interfacial states could give rise to a new design and architecture of 2D functional devices. Here, we report a 2D non-volatile vdWH memory device enabled by the artificially created interfacial states between hexagonal boron nitride (hBN) and molybdenum ditelluride (MoTe2). The memory originates from the microscopically coupled optical and electrical responses of the vdWH, with the high reliability reflected by its long data retention time over 10^4 s and large write-erase cyclic number exceeding 100. Moreover, the storage currents in the memory can be precisely controlled by the writing and erasing gates, demonstrating the tunability of its storage states. The vdWH memory also exhibits excellent robustness with wide temperature endurance window from 100 K to 380 K, illustrating its potential application in harsh environment. Our findings promise interfacial-states engineering as a powerful approach to realize high performance vdWH memory device, which opens up new opportunities for its application in 2D electronics and optoelectronics.

Optimization of Mechanically Assembled Van Der Waals Heterostructure Based On Solution Immersion and Hot Plate Heating

Layers of two-dimensional material are bonded together by van der Waals force, as a result, there is no need to take into consideration of the lattice mismatch in the formation of heterojunction, which is endowed with the characteristics of simple stacking in method, free of limitation to the type of materials and diverse changes. However, although the Van Der Waals heterojunction is relatively easy to stack, it is still difficult to generate inter-layer coupling between the thin crystal layers that form the Van Der Waals heterojunction. In most cases, the stacked heterojunction is simply stacked together without any new effects. Therefore, the realization of heterojunction coupling is a difficult problem to be considered in the process of preparing Van Der Waals heterojunction. In this paper, a method based on solution immersion and hot plate heating is proposed to optimize the mechanical stacking of Van Der Waals heterojunctions. It is found that the heterojunctions prepared by normal mechanical stacking method are usually uncoupled before treatment, but they can be stably coupled after treatment. Our method, simple, fast with low-cost, has been repeatedly verified to have a high success rate of coupling, which is suitable for most experimental groups to use and reproduce.

An ultrafast photodetector driven by interlayer exciton dissociation in a van der Waals heterostructure

We model interlayer exciton transport in van der Waals heterostructures to propose devices based on interlayer exciton dissociation in split-gate geometries for ultrafast photodetector applications.