Fig. 2: Material characterizations of OCPM device.

a Schematical diagram of the OCPM. b Polarization-sensitive absorption spectra mapping of the ReS2 layer. EAP means exciton absorption peak. The rotation angle is with respect to the b-axis in-plane clockwise. c Polarization-sensitive absorption spectra mapping of the GeSe2 layer. The rotation angle is with respect to the b-axis in-plane clockwise. d Typical angle-resolved polarized Raman spectra mapping of the ReS2/GeSe2 bi-layer. e The angle-dependent Raman intensity of the A1g mode for ReS2. f The angle-dependent Raman intensity of the A1g mode for GeSe2. g The cross-section of the ReS2/GeSe2 bilayer and the corresponding element distribution. h The fast Fourier transform (FFT) pattern of ReS2. ZA means zone axis. i The fast Fourier transform (FFT) pattern of GeSe2.