Figure 3. Photodetector performance.

(a) The responsivity (left axis) as a function of reverse bias under 975 nm (1.31 eV) illumination displays a sharp increase at the field-emission onset, and a photomultiplicative gain (right axis) exceeding unity above 2 V reverse bias. An increase of over a two-orders of magnitude is recorded before breakdown occurs. (b) The EQE spectra at different biases showcases the contribution of the quantum-dots at the infrared. A 60-fold enhancement is obtained at the exciton peak (Supplementary Fig. 8). (c) The photoresponse dynamics at 1 V reverse bias are characterized by a sub 10 μs fall time with a corresponding 3-dB bandwidth of 60 kHz. (d) Responsivity-bias and time response were characterized using 975 nm monochromatic illumination at a fluence of 100 μW cm⁻². Error bars correspond to the s.d. over 20 measurements.