Dipole and bowtie nano-antenna for carbon nanotube (CNT) based infrared sensors

We report the fabrication and experimental characterization of two different designs of nanoantenna for carbon nanotube (CNT) based infrared (IR) sensors. By designing a nanosized antenna and integrating with CNT sensing element, the electric field intensity at the position of the sensing element can be enhanced and so a very sensitive infrared nanosensor is developed. The efficiency and characteristics of the two different nanoantenna geometries were studied experimentally by measuring the photocurrent response of the sensor before and after the nanoantenna is implemented. The experimental result has shown the nano antenna increases the photocurrent by more than 10-fold and the bowtie antenna produces a bigger enhancement factor. This implies that the electric field in the vicinity of the detector is enhanced by the nanoantenna. The proposed design and analysis enables a reliable method to enhance the efficiency of the ultra-small sensing elements, which are important to the development of a range of novel functional infrared devices and systems.