Strong electrically tunable MoTe2/graphene van der Waals heterostructures for high-performance electronic and optoelectronic devices

MoTe2 is an emerging two-dimensional layeredmaterial showing ambipolar/p-type conductivity, which makes it an important supplement to n-type two-dimensional layeredmaterial like MoS2. However, theproperties based on its van der Waals heterostructures have been rarely studied. Here, taking advantage of the strongFermi level tunability ofmonolayergraphene (G) and the feature of van der Waals interfaces that is free fromFermi level pinning effect, wefabricate G/MoTe2/G van der Waals heterostructures and systematically study the electronic and optoelectronicproperties. We demonstrate the G/MoTe2/GFETs with low Schottky barriers for both holes (55.09  meV) andelectrons (122.37  meV). Moreover, the G/MoTe2/G phototransistors show high photoresponse performances with on/off ratio, responsivity, and detectivity of ∼105, 87  A/W, and 1012 Jones, respectively. Finally, we find the response time of the phototransistors is effectively tunable and a mechanism therein is proposed to explain our observation. This work provides an alternative choice of contact for high-performancedevices based on p-type and ambipolar two-dimensional layeredmaterials.

Source: Applied Physics Letters - November 8, 2016 Category: Physics Authors: Feng Wang, Lei Yin, Zhenxing Wang, Kai Xu, Fengmei Wang, Tofik Ahmed Shifa, Yun Huang, Yao Wen, Chao Jiang and Jun He Source Type: research