Fig. 2: Characterization of a ReS2/ReS2 homostructure device.
From: Strong bulk photovoltaic effect in engineered edge-embedded van der Waals structures
a Optical image of the ReS2/ReS2 homostructure device. Left (xL) and right (xR) edges, including edge-embedded structures, are denoted by blue and red solid lines. The bottom and top ReS2 flakes are enclosed by black and red dashed lines, respectively. Scale bar is 10 μm. b Schematic of the short-circuit non-local photocurrent measurements. c–f Cross-sectional STEM of edge-embedded structures in the ReS2/ReS2 homostructure. d and f show the enlarged regions of left and right edge-embedded structures, respectively. g Non-local photocurrents, detected by electrodes 2 and 3, along left (blue dots) and right (orange dots) edges. Purple shaded region shows the position of edge-embedded structures. Yellow shaded regions show the position of electrodes. Opposite-directional photocurrents are observed along left and right edge-embedded regions. h Normalized BPVE-induced photocurrent along edges using IBPVE = ±(Iph(xL)-Iph(xR))/2. A peak feature is observed in the edge-embedded regions. i Non-local photocurrents along x direction at y = 20 μm. Blue and red dashed lines show the position of vdW edges. j Linear-polarization-dependent non-local photocurrents at three representative positions A, B, and C, marked in a. Dots are experimental results and solid lines are fitting curves using the expression Asin(2θ + ϕ), where A is the amplitude and ϕ is the phase. Light polarization degree θ is the angle between light polarization and x-direction.
