No abstract

Multilayer graphene is considered a promising material for various optoelectronic devices. To exploit its intriguing electronic properties, an electric field must be achieved inside this material. However, creation of a desired electric field in multilayer graphene is difficult because any external electric field is mostly screened by its outermost surface. Here, we report a one-step chemical vapor deposition method for the synthesis of Bernal-like stacked graphene with a built-in vertical electric field that can be tuned over a wide range. This method can be used to control the optoelectronic properties of graphene in the synthesis stage. Owing to this built-in vertical electric field and Bernal-like stacking, the synthesized graphene exhibits vertical photovoltaic effects, which is very promising for various optoelectronic applications.

No abstract

The evolution of surface cleanliness and the electronic properties-Dirac voltage(V Dirac ), hysteresis and mobility (μ) of a graphene field-effect transistor (GFET)-were monitored by measuring lateral force microscopy and drain current (I D ) as a function of gate voltage (V G ), after mechanically cleaning the surface, scan-by-scan, with contact-mode atomic force microscopy. Both the surface cleanliness and the electronic properties evolved, showing a sudden improvement and then saturation for a mobility of around 2200 cm 2 V −1 s −1 . We found that the mobility suppression of the as-fabricated GFET deviated from a randomly distributed impurities model, which predicted a greater mobility than obtained from the measured V Dirac . Therefore, the substrate impurities are excluded from the origins of the extraordinary suppression of the mobility, and the possible origin will be discussed.

No abstract