Graphene-germanium quantum dot photodetector with high sensitivity

Graphene-based photodetectors have attracted strong interest for realizing optoelectronic devices, including photodetectors. Here we report a simple fabrication of graphene-germanium quantum dots for broadband light detection from visible to infrared region. The photodetectors show an improved responsivity and response speed. Specifically, the fabricated germanium quantum dots on graphene photodetector shows a responsivity of 1,500 A/W at room temperature and the response time is as fast as ~ 1 ms. These results address key challenges for broadband photodetectors from visible to infrared region, and are promising for the development of graphene-based optoelectronic applications.