A Fully Transparent and Flexible Ultraviolet-Visible Photodetector Based on Controlled Electrospun ZnO-CdO Heterojunction Nanofiber Arrays

It is essential for novel photodetectors to show good photoresponses, high stability, and have facile fabrication methods. Herein, an optimized electro-spinning method to fabricate a photodetector based on nanowire arrays that has a wide spectral response range is demonstrated. Arrays of ZnO-CdO hybrid nanowires are carefully fabricated fusing ZnO and CdO portions into the same nanowires and subsequently assembling those nanowires into a regular structure. Compared to pure ZnO or CdO nanowire arrays, the hybrid arrays show comparable photocurrent/dark current ratios and response speeds, but they possess a much wider spectral response range from ultraviolet to visible light. The optoelectronic and electronic properties of the ZnO-CdO hybrid nanowire arrays are systematically explored. Based on this, a transparent and flexible photodetector made of ZnO-CdO hybrid nanowire arrays is fabricated. It shows a high transparency of around 95% in the spectral range of 400-800 nm and maintains its properties even after 200 bending cycles. Importantly, the developed, simple method can be directly applied to many types of substrates and a transfer of the nanowires becomes unnecessary, which guarantees a high quality of the devices.