Fig. 3: Device characterization and carrier dynamics under illumination.

a I_ph under light (532 nm laser) vs V_MG, with V_SG changing from −2 to 2 V. An increase in I_ph is observed due to charge separation at the lateral p–n junction leading to an inflow of holes into the MG channel. b Band diagrams across SG-MG-SG showing efficient (holes towards the channel and electrons towards the SG regions) photogenerated e-h separation at the diode depletion regions, going from p⁺_S–p_M–p⁺_S to n_S–p_M–n_S configuration. c Responsivity calculated from I_ph shows a 24x increase (for fixed V_MG = −0.5 V and V_D = 1 V) in going from p⁺_S–p_M–p⁺_S to n_S–p_M–n_S configuration along the SG-MG-SG direction. d I_ph against input optical power shows a sublinear dependency for V_SG = −2 and 2 V and without V_SG indicating the presence of trap states in the WSe₂ channel.