An invisible metal-semiconductor photodetector

Nanotechnology has enabled the realization of hybrid devices and circuits in which nanoscale metal and semiconductor building blocks are woven together in a highly integrated fashion. In electronics, it is well known how the distinct material-dependent properties of metals and semiconductors can be combined to realize important functionalities, including transistors, memory and logic. We describe an optoelectronic device for which the geometrical properties of the constituent semiconductor and metallic nanostructures are tuned in conjunction with the materials properties to realize multiple functions in the same physical space. In particular, we demonstrate a photodetector in which the nanoscale electrical contacts have been designed to render the device 'invisible' over a broad frequency range. The structure belongs to a new class of devices that capitalize on the notion that nanostructures have a limited number of resonant, geometrically tunable optical modes whose hybridization and intermodal interference can be tailored in a myriad of useful ways.