Fig. 1. (Color online) (a) XRD pattern of ZnO thin film. (b) XRD patterns of BiOCl on Cu foil substrate and Cu foil. (c) Optical absorption spectra of BiOCl nanoflakes and ZnO thin film.

Fig. 2. SEM images of BiOCl on Cu foil at different levels of magnification.

Fig. 3. (Color online) (a) Top view AFM image of ZnO thin film at a scale of 5 × 5 μm². (b) Section profile of ZnO thin film. (c) 3D AFM image of ZnO thin film.

Fig. 4. (a) TEM image, (b) HRTEM image, and (c) SAED pattern of the BiOCl nanoflakes samples.

Fig. 5. (Color online) (a) Schematic diagram of the p-BiOCl/n-ZnO photodetector with back-side light irradiation. (b) I–V curve of In–ZnO–In device in dark. (c) I–V curve of p-BiOCl/n-ZnO photodetector in dark, inset is the I–V curves of the device in dark and under 350 nm light illumination at logarithmic scale. (d) I–V curve of Cu–BiOCl–Cu device in dark. (e) Logarithmic scale I–V curves of In–ZnO–In device in dark and under 350 nm light illumination. (f) Logarithmic scale I–V curves of Cu-BiOCl-Cu device in dark and under 350 nm light illumination.

Fig. 6. (Color online) The photoresponse spectra of the p-BiOCl/n-ZnO photodetector at different (a) negative biases and (b) positive biases. (c) Schematic energy band diagram of the device.

Fig. 7. (Color online) (a) Time response (“on” and “off” states) characteristic of the p-BiOCl/n-ZnO photodetector under 350 nm (0.304 mW/cm²), 400 nm (0.386 mW/cm²), and 450 nm (0.426 mW/cm²) light illumination at –3 V. (b) Normalized time response of the p-BiOCl/n-ZnO photodetector under 350 nm (0.304 mW/cm²) illumination at –3 V. (c) Single period time response of the In–ZnO–In photodetector under 350 nm (0.304 mW/cm²) illumination at –3 V. (d) Single period time response of the Cu–BiOCl–Cu photodetector under 350 nm (0.304 mW/cm²) illumination at 3 V.