A high response MoS2-graphene hetero-junction photodetector with broad spectral range

Two dimensional (2D) crystal materials like graphene, MoS
2
, and hexagonal BN, have exciting electrical, mechanical, and optical properties [1]. Photo responses of 7.5mA/W [2] and 110mA/W [3] have been reported in MoS
2
photodetectors. The upper limit of the spectral range in multi-layer MoS
2
detectors is approximately 700nm, which is determined by the material bandgap [4]. Graphene photodetectors have a wide spectral range from 300 to 2500nm [5] but they have a lower response (0.25mA/W [6] and 1mA/W [7]) than to MoS
2
devices. In this paper, we demonstrate a novel MoS
2
-graphene hetero junction photodetector spanning a wide spectral response from visible to infrared with a photoconduction responsivity of 24.2mA/W at 520nm and 2.1mA/W at 1.01μm.