Fig. 1. (Color online) Schematic diagram of the tube furnace setup for the growth of CsPbBr₃/PbS heterostructures.

Fig. 2. (Color online) (a) SEM image of PbS single-crystal films epitaxially grown on NaCl (100) substrates. (b) XRD patterns of the PbS films on NaCl (100) crystals (red) and reference data (JPCDS, PDF#05-0592, black).

Fig. 3. (Color online) (a, b) Cross-section and top-view SEM images of CsPbBr₃ films epitaxially grown on PbS (100) films. (c) XRD patterns of the CsPbBr₃/PbS heterostructures and standard cards of CsPbBr₃ and PbS. (d) Magnified XRD pattern in (a).

Fig. 4. (Color online) (a, b) Experimental results of pole figures from EBSD results for CsPbBr₃ and PbS. (c) EBSD orientation map of the CsPbBr₃ films epitaxial growth on PbS.

Fig. 5. (Color online) (a) UV–visible–IR absorption spectra and (b) PL spectra of pristine CsPbBr₃ and CsPbBr₃/PbS heterostructures.

Fig. 6. (Color online) Photodetector based on CsPbBr₃/PbS film heterostructures. (a) I–V curves of the film photodetector in the dark and under 450 nm laser illumination with different light intensities. The inset is the schematic diagram of the device. (b) Light intensity dependence of the photocurrent at the bias of 5 V and corresponding fitting curve. (c, d) Time-resolved photoresponse and the enlarged portion of the device at the bias of 5 V and light intensity of 40 mW/cm².

Fig. 7. (Color online) (a) Schematic diagram of the CsPbBr₃/PbS p–n heterojunction photodetector under laser illumination. (b) Dark current and photocurrent of the CsPbBr₃/PbS heterostructure detectors under a 532, 785 and 1550 nm light with a power density of 40 mW/cm².