Graphene and silver combined to create photodetectors with increased ability to detect UV light

Researchers from the Indian Institute of Science (IISc), the Max Planck Institute for Intelligent Systems in Germany and the University of Stuttgart, Germany have developed a novel silver nanoparticle-graphene hybrid photodetector device with an increased ability to detect Ultraviolet light.

To enhance graphene's interaction with light, researchers have proposed several strategies. One of these strategies has been to sensitize the graphene with plasmonic nanostructures, to form a graphene-plasmonic hybrid system. Plasmonic nanoparticles are particles which show an increased interaction with light of wavelength larger than the particle itself. These particles are said to interact with light waves through an oscillation of their internal electric fields, as the light hits the particle. Previous studies have demonstrated enhanced visible and infrared light detection efficiency in graphene-plasmonics hybrid materials. However, these devices haven’t been efficient at detecting ultraviolet (UV) light.

In their new study, the researchers wanted to develop a graphene-plasmonics hybrid material with enhanced UV light detection abilities. For the study, silver nanoparticles were chosen as the plasmonics particles, which were decorated with graphene, to form the hybrid structure.

The researchers employed self-assembly and physical shadow growth techniques to fabricate a regular large-area array of silver nanoparticles, each measuring around 50 nanometers. Onto this array, graphene is deposited using chemical vapor deposition technique, where graphene vapor is incident on the nanoparticles to form a layer of graphene on them. The device fabrication strategy is scalable and modular remark the authors, making it easier to commercialize the process.

The new silver nanoparticle-graphene hybrid device showed an enhanced ability to interact with light of wavelength ranging between 330 nanometers to 450 nanometers. Furthermore, when lower wavelengths of light were used, the researchers measured an even higher responsivity from the hybrid device corresponding to an impressive 10000 times increase over the responsivity of native graphene. If commercialized, the material could greatly increase the ability to detect ambient UV light.

Posted: May 27,2018 by Ron Mertens