The carbon dots modified ZnO films photodetector with broadband and fast photoresponse

The ZnO films is a common candidate for photodetectors. However, the performance of photodetectors based on ZnO films fabricated by traditional sol-gel spin coating method is restricted to narrow absorption range and persistent photoconductance caused by defects. Herein, the carbon quantum dots (CDs) prepared by hydrothermal method are hybridized with the ZnO film to fabricate the ZnO/CDs hybrid photodetector. The transmission electron microscope (TEM) measurement confirmed that the existence of ZnO and CDs as well as the fabrication of ZnO/CDs hybrid structure. Owing to the wide absorption range of CDs, the ZnO/CDs photodetector demonstrated broadband photoresponse from UV (300–360 nm) to visible range (400–600 nm) compared with the ZnO photodetector. Meanwhile, the ZnO/CDs photodetector possesses the faster response that the rise time decreased from 180.93 to 5.94 s and the decay time reduced from 329.05 to 0.77 s. This work provides a useful approach to improve the optoelectronic performance of ZnO films photodetectors fabricated by sol-gel spin coating method.