Search

Non-uniform photocurrent is usually generated at the overlapped region of the heterostructures, and its potential applications may be hindered by the spatial uniformity issue of the device photoresponse. Here, nearly a uniform photoresponse at the overlapped region of the thermally oxidized Ni and molybdenum disulphide (MoS2) heterostructures is obtained. Further characterizations reveal that several nanometers Ni is rightly under the NiOx layer formed at the surface of the film in the oxidation process. The heterostructures based on layered MoS2/NiOx/Ni with highly conductive bottom Ni show a high uniform photoresponse with an external quantum efficiency (EQE) of 1.4% at 532 nm. Moreover, successful integration of multiple devices suggests a great priority for such a structure for highly integrated uniform photodetectors. [ABSTRACT FROM AUTHOR]

Van der Waals epitaxy growth of two-dimensional materials promise controllable fabrication of novel artificial heterostructures. Here, we report molecular beam epitaxy growth of continuous molybdenum ditelluride (MoTe 2 ) films on graphene substrates with good stoichiometry in both 2H and 1T′ phases. Post-growth annealing reveal phase transition suppressed in Te-rich atmosphere, through in-situ scanning tunneling microscopy/spectroscopy and X-ray photoelectron spectroscopy. Our results suggest a new route to fabricate atomically ultrathin MoTe 2 lateral heterophase homojunctions, showing potential applications in future lateral thin-film transistors. [ABSTRACT FROM AUTHOR]

Two-dimensional layered heterostructures show great potential to develop optoelectronic systems. Here, we have investigated the photoresponse properties of two contact interfaces in few-layer graphene–WSe 2 heterostructures. The photoresponsivity of graphene–WSe 2 contact interface is about 2.67 mA/W, and the photoresponsivity of WSe 2 –metal contact interface is about 0.2 mA/W. Photocurrent images show that the two contact interfaces behave differently under drain voltage from − 0.5 V to 0.5 V. The photoresponsivity of one contact interface increases with the drain voltage, and that of the other decreases with the drain voltage. Experimental results and band diagram studies prove that the photoresponse properties of contact interfaces are tuned by small drain voltage. This study will be beneficial for understanding the effect of drain voltage on the heterostructures. [ABSTRACT FROM AUTHOR]