Integrated ultraviolet sensor using zinc oxide nanorods by ac-electric-filed-assisted growth method

In this paper, we report an integrated ultraviolet (UV) sensor fabricated using a hybrid technique incorporating “bottom-up” with “top-down” methods. The sensor is with single crystalline ZnO nanorods directly growing onto a coplanar metallic electrode-pair on a silicon substrate using an electric-field-assisted wet chemical method at a low temperature (75°C). Poly diallyldimethylammonium chloride (PDADMAC) is used as a surface coating material for surface functionalization to enhance the UV response of ZnO nanorods. An integrated UV sensor is realized by connecting the prepared ZnO-nanorods element packaged with a thin layer of polydimethylsiloxane (PDMS) into a constant current mode circuit to form a complete device, which demonstrates a response time of 13s and a photosensitivity of 3.5V to the turn-on of 108.5mW/cm² UV illumination.