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Photodetectors have widespread applications in fields including telecommunications, thermal imaging and bio-medical imaging. The photogating effect, arising from charge trapping at defects and/or interfaces, can have extremely high photoelectric gain which can be a benefit to high-sensitivity room temperature photodetection. Here, we introduce thin layered organic charge transfer complexes (CPXs) integrated on graphene transistors for the development of hybrid phototransistors with ultra-high photoresponsivity of ∼106 A W-1 in the near infrared (NIR) region at room temperature. Our study has demonstrated a graphene-organic CPX with a broadband photoresponse ranging from the visible to the NIR region. The high photoelectric gain was from the photogating effect at the graphene/CPX interface. In addition, the photoresponse properties of the graphene-organic CPX can be regulated by electrical gating of graphene.

Interfacial engineering, such as molecule intercalation, can modify properties and optimize performance of van der Waals heterostructures and their devices. Here, we investigated the pristine and water molecule intercalated heterointerface of niobium disulphide (NbS

Interfacial engineering, such as molecule intercalation, can modify properties and optimize performance of van der Waals heterostructures and their devices. Here, we investigated the pristine and water molecule intercalated heterointerface of niobium disulphide (NbS2) on hexagonal boron nitride (h-BN) (NbS2/BN) using advanced atomic force microscopy (AFM), and observed the metal-insulator transition (MIT) of first layer (1L-) of NbS2 induced by water molecule intercalation. In pristine sample, interfacial charge transfers were confirmed by the direct detection of trapped static charges at the post-exposed h-BN surface, produced by mechanically peeling off the 1L-NbS2 from the substrate. The interfacial charge transfers facilitate the intercalation of water molecules at the heterointerface. The intercalated water layers make a MIT of 1L-NbS2, while the pristine metallic state of the following NbS2 layers remains preserved. This work is of great significance to help understand the interfacial properties of 2D metal/insulator heterostructures and can pave the way for further preparation of an ultrathin transistor.

With its atomically smooth surface yet no dangling bond, chemical inertness and high temperature sustainability, the insulating hexagonal boron nitride (h-BN) can be an ideal substrate for two-dimensional (2D) material growth and device measurement. In this review, research progress on the chemical growth of 2D materials on h-BN has been summarized, such as chemical vapor deposition and molecular beam epitaxy of graphene and various transition metal dichalcogenides. Further, stacking of the as-grown 2D materials relative to h-BN, thermal expansion matching between the deposited materials and h-BN, electrical property of 2D materials on h-BN have been discussed in detail.