Solar-blind ultraviolet-visible dual-spectral photodetector based on carbon nanodots/flexible-silicon heterojunction

Flexible solar-blind ultraviolet (UV) photodetectors (PDs) have important applications in biomedical and wearable electronic devices. Herein, a dual-spectral carbon nanodots/flexible n-silicon heterojunction photo-detector is reported that always shows a photo response in UV illumination, while in visible illumination there is a photo response only in forward bias. The working mechanism of the carbon nanodots/silicon heterojunction was investigated. At 5 V bias, the responsivity of the device was 30.5 mA/W and 93.7 mA/W under the 254 nm illumination and the visible illumination, respectively. And the detectivity was 1.61 x 1011 Jones and 2.14 x 1011 Jones, respectively. The photocurrent of the device can reach 91 % or more of the original under the 0-0.6 % bending strain.