Simple fabrication of SWIR detectors based on wet deposition of carbon nanotubes and quantum dots

Abstract

Over the last two decades, carbon based materials and especially carbon nanotubes (CNTs), were the subject of many studies, mainly due to their unique electrical, optical and mechanical properties (Ouyang et al., 2002; Dresselhaus et al., 2003; Dresselhaus et al., 1995). CNTs can combine electrical conductivity with wide absorption spectra, and can be produced in large scale (Danafar et al., 2009) [4]. These properties enable to realize CNTs in simple, low-cost detector. Here we present a proof-of-concept for such a detector operating at the short-wave infrared (SWIR) regime. We use a simple spray technique, which allows creating a large matrix of CNT bundles. Semiconducting quantum dots (QDs) were adsorbed on top of the CNTs, enhancing the sensitivity to the infrared regime. This regime is important for numerous applications in the civil, medical, defense and security fields. Controlled coupling between the QDs and the CNT matrix generates gate-like electro-optical response when light is absorbed. This proof-of-concept for a detector in the SWIR region is presented for large surfaces and substrates, while the responsivity and detectivity of the detector in a range of frequencies and wavelengths was evaluated.