Stretchable SnO₂-CdS interlaced-nanowire film ultraviolet photodetectors

Stretchable ultraviolet photodetectors with fast response have wide applications in wearable electronics and implantable biomedical devices. However, most of the conventional binary oxide nanowires based photodetectors exhibit slow response due to the presence of a large number of surface defects related to trapping centers. Herein, with interlaced SnO₂-CdS nanowire films as the sensing materials, we fabricated stretchable ultraviolet photodetectors with significantly improved response speed via a multiple lithographic filtration method. Systematic investigations reveal that the interlaced-nanowire based photodetectors have lower dark current and much higher response speed (more than 100 times) compared with pure SnO₂ nanowire based photo-detectors. The relevant carrier generation and transport mechanism were also discussed. In addition, due to the formation of waved wrinkles on the surface of the nanowires/PDMS layer during the prestretching cycles, the SnO₂-CdS interlaced nanowire photodetectors display excellent electrical stability and stretching cyclability within 50% strain, without obvious performance degradation even after 150 stretching cycles. As a simple and effective strategy to fabricate stretchable ultraviolet photodetectors with high response speed, the interlaced-nanowire structure can also be applied to other nanowire pairs, like ZnO-CdS interlaced-nanowires. Our method provides a versatile way to fabricate fast speed ultraviolet photodetectors by using interlaced metal oxide nanowires-CdS nanowires structures, which is potential in future stretchable and wearable optoelectronic devices.