Enhancement of surface inspection by Moiré interferometry using flexible reference gratings

A stretchable crumpled graphene photodetector with plasmonically enhanced photoresponsivity

Graphene has been widely explored for flexible, high-performance photodetectors due to its exceptional mechanical strength, broadband absorption, and high carrier mobility. However, the low stretchability and limited photoabsorption of graphene have restricted its applications in flexible and highly sensitive photodetection systems. Various hybrid systems based on photonic or plasmonic nanostructures have been introduced to improve the limited photoresponsivity of graphene photodetectors. In most cases, the hybrid systems succeeded in the enhancement of photoresponsivity, but showed limited mechanical stretchability. Here, we demonstrate a stretchable photodetector based on a crumpled graphene-gold nanoparticle (AuNP) hybrid structure with ∼1200% enhanced photoresponsivity, compared to a conventional flat graphene-only photodetector, and exceptional mechanical stretchability up to a 200% tensile strain. We achieve plasmonically enhanced photoresponsivity by integrating AuNPs with graphene. By crumpling the hybrid structure, we realize mechanical stretchability and further enhancement of the optical absorption by densification. We also demonstrate that our highly stretchable photodetector with enhanced photoresponsivity can be integrated on a contact lens and a spring structure. We believe that our stretchable, high performance graphene photodetector can find broad applications for conformable and flexible optical sensors and dynamic mechanical strain sensors.