Fig. 3: Mechanisms of the device under different bias voltages.

a Transfer curves (I_ds−V_gs) of the MoSe₂/PdSe₂ device under 785 nm illumination with different power densities (V_ds = 1 V). ∆V_gs and the shaded area represent the specific value and range of the change of the charge neutrality point, respectively. b Output current distribution as a function of bias voltages V_ds and back gate voltages V_gs. Inset: The change in the on/off ratio of the device at various source–drain voltages. c Extracted device responsivities, R (solid lines), and detectivities, D* (dashed lines), at V_ds = −1, 0, and 1 V, respectively. d Relative response with different light modulation frequency measured. The −3 dB cutoff is marked by the horizontal dashed line. Inset: Single magnified response curves at V_ds = −1, 0, and 1 V. The vertical dashed lines in the inset represent 10% and 90% of the photocurrent used to evaluate the rise/fall time of the device. e Fowler–Nordheim plots of the device at positive V_ds in the dark and under illumination. The dashed lines are the fits to the experimental data. f Temperature-dependent transport characteristics of the MoSe₂/PdSe₂ heterostructure device in the dark.