Multiarray Nanopattern Electronic Nose (E-Nose) by High-Resolution Top-Down Nanolithography

Abstract

An electronic nose (E-nose) is an artificial sensing device that mimics the human olfactory system using a multiarray sensor system. However, since the design and fabrication of multiarray sensing channels are significantly limited because of the requirement of time-consuming and nonuniversal processes, the development of commercializable and high-throughput fabrication approaches are critically required. Herein, high-resolution top-down lithography is developed for E-nose fabrication for the first time. Five different metal oxide semiconductor (MOS) nanopattern channels (NiO, CuO, Cr2O3, SnO2, and WO3) are fabricated into multiarray sensors with high-throughput using a unique lithographic approach that utilizes the sputtering of grains of the metals via low-energy ion plasma bombardment. The nanopattern channels show i) high-resolutions (15 nm scale), ii) high-aspect-ratios (11; 14 nm width and 150 nm height), and iii) ultrasmall grains (5.1 nm) with uniformity on a cm(2) scale, resulting in high sensitivity toward the target analytes. The E-nose system, which is composed of five MOS nanopattern channels, can successfully distinguish seven different hazardous analytes, including volatile organic compounds and nitrogen-containing compounds. It is expected that this unique lithography approach can provide a simple and reliable method for commercializable channel fabrication, and the E-noses can have further applications in real-life situations.