Fig. 5: Enhanced near-infrared polarization photodetector with configurable polarity transition.

a The polarization photocurrent of 0° and 90° increase with the light power increasing step-by-step from zero to 0.37 W/cm². The incident light is 1270 nm. b Anisotropic photocurrent response under different excitation powers at 1550 nm at 0 V bias shown in the polar plots. The incident power from P1 to P7 is 180 nW, 1.8 μW, 18 μW, 180 μW, 1.8 mW, and 3.4 mW. c Excitation power dependence of the polarization ratio extracted from Fig. 5b. In the low-power region, the PR value decreases sharply. d The output characteristics of devices under different polarization angle lights with the same excitation power (180 μW). e Polarization photocurrent ratio (symbols), which is defined as I_θ/I_θ=90°, extracted from Fig. 5d. The black solid line is fitted with a hyperbola model. The blue and yellow regions indicate the unipolar (PR  >  0) and bipolar (PR  <  0) PR values. f Polarization photocurrent ratio (I_θ/I_θ=90°) with a bias of −37 mV under illumination of 1550 nm. The laser power is about 180 μW. g, h, i Measured (symbols) and fitted (lines) photoresponse of the device at V_bias1 (V_bias1 = -37 mV), V_bias2 (V_bias2 = −49 mV) and V_bias3 (V_bias3 = −59 mV).