Hybrid graphene/cadmium-free ZnSe/ZnS quantum dots phototransistors for UV detection

Yi-Lin Sun; Dan Xie; Meng-Xing Sun; Chang-Jiu Teng; Liu Qian; Ruo-Song Chen; Lan Xiang; Tian-Ling Ren

doi:10.1038/s41598-018-23507-y

Hybrid graphene/cadmium-free ZnSe/ZnS quantum dots phototransistors for UV detection

Sci Rep. 2018 Mar 23;8(1):5107. doi: 10.1038/s41598-018-23507-y.

Authors

Yi-Lin Sun¹, Dan Xie², Meng-Xing Sun¹, Chang-Jiu Teng¹, Liu Qian³, Ruo-Song Chen⁴, Lan Xiang⁴, Tian-Ling Ren¹

Affiliations

¹ Institute of Microelectronics, Tsinghua National Laboratory for Information Science and Technology (TNList), Tsinghua University, Beijing, 100084, People's Republic of China.
² Institute of Microelectronics, Tsinghua National Laboratory for Information Science and Technology (TNList), Tsinghua University, Beijing, 100084, People's Republic of China. xiedan@tsinghua.edu.cn.
³ Department of Chemistry, Tsinghua University, Beijing, 100084, People's Republic of China.
⁴ Departmentof Chemical Engineering, Tsinghua University, Beijing, 100084, People's Republic of China.

Abstract

Graphene-based optoelectronic devices have attracted much attention due to their broadband photon responsivity and fast response time. However, the performance of such graphene-based photodetectors is greatly limited by weak light absorption and low responsivity induced by the gapless nature of graphene. Here, we achieved a high responsivity above 10³ AW^-1 for Ultraviolet (UV) light in a hybrid structure based phototransistor, which consists of CVD-grown monolayer graphene and ZnSe/ZnS core/shell quantum dots. The photodetectors exhibit a selective photo responsivity for the UV light with the wavelength of 405 nm, confirming the main light absorption from QDs. The photo-generated charges have been found to transfer from QDs to graphene channel, leading to a gate-tunable photo responsivity with the maximum value obtained at V _G about 15V. A recirculate 100 times behavior with a good stability of 21 days is demonstrated for our devices and another flexible graphene/QDs based photoconductors have been found to be functional after 1000 bending cycles. Such UV photodetectors based on graphene decorated with cadmium-free ZnSe/ZnS quantum dots offer a new way to build environmental friendly optoelectronics.