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

• Published in: Advanced functional materials Vol. 30; no. 27
• Main Authors: Kang, Hohyung, Cho, Soo‐Yeon, Ryu, Jin, Choi, Junghoon, Ahn, Hyunah, Joo, Heeeun, Jung, Hee‐Tae
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.07.2020
• Subjects: Channels; electronic nose; Electronic noses; gas sensors; Ion bombardment; Materials science; Metal oxide semiconductors; multiarray; Nanolithography; principal component analysis; Smell; Tin dioxide; VOCs; Volatile organic compounds
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202002486

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 cm2 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. High‐resolution top‐down lithography is used to develop a multiarray nanopatterned electronic nose. It demonstrates a unique nanolithography, with five distinct metal oxide semiconductor channels with 15 nm resolution and 5.1 nm grain size fabricated using an identical method and achieving successful segregation of seven different gases. This unique top‐down approach can provide a reliable method for channel diversification on a commercial level.