TUNABLE PHOTOCURRENT GENERATION IN HETEROSTRUCTURES OF TWO DIMENSIONAL LAYERED MATERIALS

摘要

The layered materials such as graphene and MoS2 have recentlynemerged as an exciting material system for future electronics andnoptoelectronics. Vertical integration of layered materials can enablenthe design of novel electronic and photonic devices.1-2 Here we reportnhighly efficient photocurrent generation from verticalnheterostructures of layered materials. We show that the verticallynstacked graphene-MoS2-graphene and graphene-MoS2-metalnjunctions can be created with a broad junction area for efficientnphoton harvesting.3 The weak electrostatic screening effect ofngraphene allows the integration of single or dual gates under and/ornabove the vertical heterostructure to tune the band slope andnphotocurrent generation. We demonstrate that the amplitude andnpolarity of the photocurrent in the gated vertical heterostructures cannbe readily modulated by the electric field of an external gate.