Researchers enhance graphene to enable multicolor photodetection

Graphene, a one-atom–thick layer of carbon lattice with a honeycomb structure, is seen as an attractive semiconductor material for use in future electronics and optoelectronics because of its speed, transparency, flexibility and strength. Recent studies have demonstrated its potential in solar cells, touch panels, ultra-fast lasers and optical modulators.

And while graphene has the potential for wideband, high-speed photodetection — the sensing of light or other electromagnetic energy — it is currently hampered by its low external sensitivity to light and its inability to differentiate different colors of light.

Now, researchers from the UCLA Henry Samueli School of Engineering and Applied Science and the department of chemistry and biochemistry in the UCLA College of Letters and Science have found that by coupling graphene with metallic plasmonic nanostructures, they can overcome these limitations, greatly enhancing the local light intensity, improving overall light sensitivity and enabling the highly specific detection of multiple colors. Such structures could be used to concentrate, guide or filter light on the nanoscale in sensors and various other devices.

Authors of the research include UCLA chemistry postdoctoral scholars Lei Liao, Hailong Zhou and Gang Liu; UCLA materials science and engineering graduate students Yuan Liu, Rui Cheng, Jingwei Bai and Lixin Liu; and UCLA assistant professor of materials science and engineering Yu Huang and UCLA assistant professor of chemistry and biochemistry Xiangfeng Duan. Professors Huang and Duan are also members of the California NanoSystems Institute at UCLA.