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Abstract
Metal oxide semiconductors have found widespread applications in chemical sensors based on electrical transduction principles, in particular for the detection of a large variety of gaseous analytes, including environmental pollutants and hazardous gases. This review recapitulates the progress in copper oxide nanomaterial-based devices, while discussing decisive factors influencing gas sensing properties and performance. Literature reports on the highly sensitive detection of several target molecules, including volatile organic compounds, hydrogen sulfide, carbon monoxide, carbon dioxide, hydrogen and nitrogen oxide from parts-per-million down to parts-per-billion concentrations are compared. Physico-chemical mechanisms for sensing and transduction are summarized and prospects for future developments are outlined.
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Jung WB, Jang S, Cho SY, Jeon HJ, Jung HT. Recent Progress in Simple and Cost-Effective Top-Down Lithography for ≈10 nm Scale Nanopatterns: From Edge Lithography to Secondary Sputtering Lithography. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1907101. [PMID: 32243015 DOI: 10.1002/adma.201907101] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/20/2019] [Indexed: 05/24/2023]
Abstract
The development of a simple and cost-effective method for fabricating ≈10 nm scale nanopatterns over large areas is an important issue, owing to the performance enhancement such patterning brings to various applications including sensors, semiconductors, and flexible transparent electrodes. Although nanoimprinting, extreme ultraviolet, electron beams, and scanning probe litho-graphy are candidates for developing such nanopatterns, they are limited to complicated procedures with low throughput and high startup cost, which are difficult to use in various academic and industry fields. Recently, several easy and cost-effective lithographic approaches have been reported to produce ≈10 nm scale patterns without defects over large areas. This includes a method of reducing the size using the narrow edge of a pattern, which has been attracting attention for the past several decades. More recently, secondary sputtering lithography using an ion-bombardment technique was reported as a new method to create high-resolution and high-aspect-ratio structures. Recent progress in simple and cost-effective top-down lithography for ≈10 nm scale nanopatterns via edge and secondary sputtering techniques is reviewed. The principles, technical advances, and applications are demonstrated. Finally, the future direction of edge and secondary sputtering lithography research toward issues to be resolved to broaden applications is discussed.
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Affiliation(s)
- Woo-Bin Jung
- Department of Chemical and Biomolecular Engineering (BK-21 Plus), Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon, 34141, Republic of Korea
- KAIST Institute for NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Sungwoo Jang
- Semiconductor R&D Center, Samsung Electronics Co., Ltd, 1, Samsungjeonja-ro, Hwaseong-si, Gyeonggi-do, 18448, Republic of Korea
| | - Soo-Yeon Cho
- Department of Chemical and Biomolecular Engineering (BK-21 Plus), Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon, 34141, Republic of Korea
- KAIST Institute for NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon, 34141, Republic of Korea
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Hwan-Jin Jeon
- Department of Chemical Engineering and Biotechnology, Korea Polytechnic University, Siheung-si, Gyeonggi-do, 15073, Republic of Korea
| | - Hee-Tae Jung
- Department of Chemical and Biomolecular Engineering (BK-21 Plus), Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon, 34141, Republic of Korea
- KAIST Institute for NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon, 34141, Republic of Korea
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The Effect of a Flow Field on Chemical Detection Performance of Quadrotor Drone. SENSORS 2020; 20:s20113262. [PMID: 32521730 PMCID: PMC7309100 DOI: 10.3390/s20113262] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/05/2020] [Accepted: 06/06/2020] [Indexed: 12/02/2022]
Abstract
The determination of a suitable sensor location on quadrotor drones is a very important issue for chemical reconnaissance platforms because the magnitude and direction of air velocity is different for each location. In this study, we investigated a customized chemical reconnaissance system consisting of a quadrotor drone and a chip-sized chemical sensor for detecting dimethyl-methylphosphonate (DMMP; a Sarin simulant) and investigated the chemical detection properties with respect to the sensor position through indoor experiments and particle image velocimetry (PIV) analysis of the system. The PIV results revealed an area free of vortex–vortex interaction between the drone rotors, where there was distinctly stable and uniform chemical detection of DMMP. The proposed chemical reconnaissance system was found to be realistic for practical application.
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