title: Hierarchical ZnO Nanowires-loaded Sb-doped SnO2-ZnO Micrograting Pattern via Direct Imprinting-assisted Hydrothermal Growth and Its Selective Detection of Acetone Molecules.
abstract: We propose a novel synthetic route by combining imprinting transfer of a Sb-doped SnO2 (ATO)-ZnO composite micrograting pattern (MP), i.e., microstrip lines, on a sensor substrate and subsequent hydrothermal growth of ZnO nanowires (NWs) for producing a hierarchical ZnO NW-loaded ATO-ZnO MP as an improved chemo-resistive sensing layer. Here, ATO-ZnO MP structure with 3-μm line width, 9-μm pitch, and 6-μm height was fabricated by direct transfer of mixed ATO and ZnO nanoparticle (NP)-dispersed resists, which are pre-patterned on a polydimethylsiloxane (PDMS) mold. ZnO NWs with an average diameter of less than 50 nm and a height of 250 nm were quasi-vertically grown on the ATO-ZnO MP, leading to markedly enhanced surface area and heterojunction composites between each ATO NP, ZnO NP, and ZnO NW. A ZnO NW-loaded MP sensor with a relative ratio of 1:9 between ATO and ZnO (1:9 ATO-ZnO), exhibited highly sensitive and selective acetone sensing performance with 2.84-fold higher response (R air/R gas = 12.8) compared to that (R air/R gas = 4.5) of pristine 1:9 ATO-ZnO MP sensor at 5 ppm. Our results demonstrate the processing advantages of direct imprinting-assisted hydrothermal growth for large-scale homogeneous coating of hierarchical oxide layers, particularly for applications in highly sensitive and selective chemical sensors.
authors.affiliation: Department of Materials Science and Engineering, Korea University, Anam-ro 145, Seongbuk-gu, Seoul 136-713, Republic of Korea.
authors.forename: Hak-Jong
authors.initials: HJ
authors.lastname: Choi
authors.affiliation: Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Seon-Jin
authors.initials: SJ
authors.lastname: Choi
authors.affiliation: Department of Materials Science and Engineering, Korea University, Anam-ro 145, Seongbuk-gu, Seoul 136-713, Republic of Korea.
authors.forename: Soyoung
authors.initials: S
authors.lastname: Choo
authors.affiliation: Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Il-Doo
authors.initials: ID
authors.lastname: Kim
authors.affiliation: Department of Materials Science and Engineering, Korea University, Anam-ro 145, Seongbuk-gu, Seoul 136-713, Republic of Korea.
authors.forename: Heon
authors.initials: H
authors.lastname: Lee