Controlled charge trapping by molybdenumdisulphide and graphene in ultrathinheterostructured memory devices

摘要

Atomically thin two-dimensional materials have emerged as promising candidates for flexibleand transparent electronic applications. Here we show non-volatile memory devices, basedon field-effect transistors with large hysteresis, consisting entirely of stacked two-dimensionalmaterials. Graphene and molybdenum disulphide were employed as both channel andcharge-trapping layers, whereas hexagonal boron nitride was used as a tunnel barrier. In theseultrathin heterostructured memory devices, the atomically thin molybdenum disulphide orgraphene-trapping layer stores charge tunnelled through hexagonal boron nitride, serving as afloating gate to control the charge transport in the graphene or molybdenum disulphidechannel. By varying the thicknesses of two-dimensional materials and modifying the stackingorder, the hysteresis and conductance polarity of the field-effect transistor can be controlled.These devices show high mobility, high on/off current ratio, large memory window and stableretention, providing a promising route towards flexible and transparent memory devicesutilizing atomically thin two-dimensional materials.