Schottky barriers formed by graphene (monolayer, bilayer, and multilayer) on 2D layered semiconductor tungsten disulfide (WS2) nanosheets are explored for solar energy harvesting. The characteristics of the graphene-WS2 Schottky junction vary significantly with the number of graphene layers on WS2, resulting in differences in solar cell performance. Compared with monolayer or stacked bilayer graphene, multilayer graphene helps in achieving improved solar cell performance due to superior electrical conductivity. The all-layered-material Schottky barrier solar cell employing WS2 as a photoactive semiconductor exhibits efficient photon absorption in the visible spectral range, yielding 3.3% photoelectric conversion efficiency with multilayer graphene as the Schottky contact. Carrier transport at the graphene/WS2 interface and the interfacial recombination process in the Schottky barrier solar cells are examined.

We investigate key electrical properties of monolayer graphene assembled by chemicalvapor-deposition (CVD) as impacted by supporting substrate material. Graphene field-effect transistors (GFETs) were fabricated with carbon channel placing directly on hexagonal boron nitride (h-BN) and SiO 2 , respectively. Small-signal transconductance ( m g ) and effective carrier mobility ( eff  ) are improved by 8.5 and 4 times on h-BN, respectively, as compared with that on SiO 2 . Compared with GFET with exfoliated graphene on SiO 2 , m g and eff  measured from device with CVD graphene on h-BN substrate exhibits comparable values. The experiment demonstrates the potential of employing h-BN as a platform material for large-area carbon electronics.