Two-step liquid phase synthesis of ZnO@CuO core–shell heterojunction nanorods arrays composites photodetectors with the enhanced UV photoelectric performances

The p-n heterojunction was established on the side surface of ZnO nanorods (NRs) by the recombination of p-type CuO and n-type ZnO to enhance the optoelectronic performances. In this work, ZnO@CuO core–shell heterojunction nanorods arrays (NRAs) composites were fabricated using sol-gel assisted hydrothermal technique and aqueous solution chemistry technique. The results display that the ZnO@CuO core–shell heterojunction NRAs composites demonstrate the enhanced absorption peaks and broad light absorption, which expand the range of ultraviolet to visible light. Compared with the ZnO NRAs photodetectors, the dark current (0.057 μA) of ZnO@CuO-2 core–shell heterojunction NRAs composites photodetectors are reduced by about 26 times, while the photocurrent (138.65 μA) of that is only reduced by about 10 times, indicating that ZnO@CuO-2 core–shell heterojunction NRAs composites photodetectors has higher photoelectric sensitivity (2432.4). The increased photoelectric sensitivity is mainly attributed to the good Schottky junction formed between ZnO NRs and CuO nanosheets accelerating the separation and transport of more photogenerated electron-hole pairs. In addition, the photoelectric response time and recovery time of ZnO@CuO-2 NRAs composites photodetectors are 46 s and 40 s. The developed ZnO@CuO core–shell heterojunction NRAs composites and the related optoelectronic properties may have a bright future in photoelectric detection field.