2D Materials and Heterostructures: from Electronic Transport to Emergent Memory, Neuromorphic and Optoelectronic Applications

Two-dimensional (2D) materials and heterostructures have emerged as promising candidates for post-Moore electronics due to their unique electronic properties and atomically thin geometry. I will start with our studies on 2D semiconductors with low lattice symmetry and type-II Weyl semimetals. In atomically thin Rhenium disulfide (ReS₂), we observed interesting low-symmetry-induced anisotropic transport and mechanical properties, and studied their electronic and optoelectronic applications.[1] In type-II Weyl semimetal Tungsten ditelluride (WTe₂), we observed planar-orientation-dependent negative longitudinal magnetoresistance (MR) which reveals important transport signatures of chiral anomaly and type-II Weyl fermions.[2] In the second part of my talk, I will show that 2D heterostructures could play important roles in future advanced memory, computing and optoelectronic applications. One example is robust memristors with good thermal stability based on a 2D heterostructure composed of graphene/MoS_2–xO_x/graphene, which show promising memory and neuromorphic applications.[3] Our latest results on the observation of ballistic avalanche phenomena in a thin 2D heterostructure made of black phosphorus and Indium Selenide (InSe), as well as their high-performance electronic and optoelectronic applications will also be presented.[4]

[1] Liu et al., Nature Comm. 6, 6991 (2015); Adv. Func. Mater. 26, 1938 (2016); Wang et al., ACS Nano 12, 9513 (2018).
[2] Wang et al., Nature Comm. 7, 13142 (2016); Nano Lett. 19, 3969 (2019); Li et al., Nano Lett. 18, 7962 (2018).
[3] Wang et al., Nature Electronics 1, 130 (2018).
[4] Gao et al., Nature Nano. 14, 217 (2019); Long et al., Science Adv. 3, e1700589 (2017).