Fig. 1. Experimental results. (a) Schematic diagram of the PbS QDs/Gr/GaN device; (b) SEM image of PbS QDs/Gr/GaN surface; (c) TEM image of PbS QDs/Gr/GaN; (d) photoluminescence spectra of GaN; (e) Raman spectra of the single-layer Gr

Fig. 2. Optoelectronic performance test results. (a)(b) I-V characteristics of the Gr/glass; (c)(d) PbS QDs/Gr/GaN photodetector with/without PbS QDs under dark and light illumination; (e) I-V and (f) I-T curves at different light power densities under 325 nm light illumination; (g) I-V diagram of devices with different concentrations of PbS QDs

Fig. 3. Fitting results. (a) Photocurrent (absolute value) dependence on light power intensity and corresponding fitting curve by the power law PbS QDs/Gr/GaN; light-power-dependent (b) R and S, and (c) D* and LDR of the PbS QDs/Gr/GaN photodetector at -2 V bias

Fig. 4. Device structure band diagram