CIOMP researchers recently found a novel material system for ultraviolet (UV) photodetectors. 

Ultraviolet (UV) photodetectors have a variety of potential applications in both civilian and military areas. In recent years many scientists have devoted to the study of UV photodetectors fabricated from Quantum quantum dots (QDs) which possess convenient integration and trap state properties. A lot of materials like CdSse, PbS, HgTe have been employed as the active layer of QD UV photodetectors. 

"Among these materials, ZnO has been considered as a promising material for UV photodetection for its wide direct bandgap, high electron saturation velocity, high irradiation resistance,etc.”, said by Prof. SHAN Chongxin, CIOMP researcher from the State Key Laboratory of Luminescence and Applications (SKLLA). 

In his article (doi:10.1038/srep07469), he mentioned “ZnO can be prepared in various nanostructures in relative simple routes, and quite a few UV photodetectors have been fabricated from ZnO QDs in literature.” 

It’s very important to use some methods to enhance the performance of ZnO QD based UV photodetectors. Carbon nanodots (CNs) may be a better choice because of some unique characters including highly luminescent characters, and good photo-bleaching resistance, etc. 

Now CNs have been mixed together with ZnO QDs to form hybrid films, and UV photodetectors have been fabricated from the hybrid films. It is found that the responsivity of the photodetector can be increased greatly with the introduction of carbon nanodots, and the detectivity and noise equivalent power of the photodetectors fabricated from the hybrid films can reach 3.1×1017 cmHz1/2/W and 7.8×10-20 W, respectively, both of which correspond to the best values ever reported for ZnO-based photodetectors. 

CIOMP scientists would continue to make research about this. 

For more details, please refer to the following link:

 http://www.nature.com/srep/2014/141212/srep07469/full/srep07469.html 

 Key words: ZnO, photodetection, carbon nanodots 

(a) Schematic illustration of the carrier generation and separation in the ZnO QDs/carbon nanodots hybrid structure; (b) Transient spectra of the emission at around 375？nm for bared ZnO QDs and ZnO/C hybrid films.(Image by SKLLA)