TY - GEN A1 - Lee, Hyunjoo J. A1 - Park, Kwan Kyu A1 - Kupnik, Mario A1 - Khuri-Yakub, Butrus T. T1 - Functionalization layers for CO2 sensing using capacitive micromachined ultrasonic transducers T2 - Sensors and Actuators B: Chemical N2 - Sensing of carbon dioxide(CO2)using inexpensive, miniaturized,and highly sensitive sensors is of great interest for environmental and consumer applications. In this paper, we present four functionalization layers that are suitable for resonant sensors based on mass-loading for CO2 detection. We compare the volume sensitivities of these layers to CO2 and relative humidity (RH) by using a highly sensitive 50-MHz capacitive micromachined ultrasonic transducer (CMUT) as a resonant sensor. Among the four function-alization layers, the layer based on a guanidine polymer exhibits the highest volume sensitivity to CO2 of 1.0 ppm/Hz in N2 and 3.8 ppm/Hz in air (∼45%RH). Furthermore, we report on other important characteristics of the guanidine polymer for sensing applications, including polymer saturation, regeneration, and repeatability. Y1 - 2012 SN - 0925-4005 IS - 174 SP - 87 EP - 93 ER - TY - GEN A1 - Lee, Hyunjoo J. A1 - Park, Kwan Kyu A1 - Kupnik, Mario A1 - Melosh, Nicholas A. A1 - Khuri-Yakub, Butrus T. T1 - Mesoporous thin-film on highly sensitive resonant chemical sensors for relative humidity and CO2 detection T2 - Analytical Chemistry N2 - Distributed sensing of gas-phase chemicals is a promising application for mesoporous materials when combined with highly sensitive miniaturized gas sensors. We present a direct application of a mesoporous silica thin film on a highly sensitive miniaturized resonant chemical sensor with a mass sensitivity at the zeptogram scale for relative humidity and CO2 detection. Using mesoporous silica thin-film, we report one of the lowest volume resolutions and a sensitive detection of 5.1 × 10–4% RH/Hz to water vapor in N2, which is 70 times higher than a device with a nontemplated silica layer. In addition, a mesoporous thin-film that is functionalized with an amino-group is directly applied on the resonant sensor, which exhibits a volume sensitivity of 1.6 × 10–4%/Hz and a volume resolution of 1.82 × 10–4% to CO2 in N2. Y1 - 2012 U6 - https://doi.org/10.1021/ac300225c SN - 1520-6882 VL - 84 IS - 7 SP - 3063 EP - 3066 ER - TY - GEN A1 - Park, Kwan Kyu A1 - Lee, Hyunjoo J. A1 - Kupnik, Mario A1 - Oralkan, Ömer A1 - Ramseyer, Jean-Pierre A1 - Lang, Hans Peter A1 - Hegner, Martin A1 - Gerber, Christoph A1 - Khuri-Yakub, Butrus T. T1 - Capacitive micromachined ultrasonic transducer (CMUT) as a chemical sensor for DMMP detection T2 - Sensors and Actuators B: Chemical Y1 - 2011 U6 - https://doi.org/10.1016/j.snb.2011.09.036 SN - 0925-4005 VL - 160 IS - 1 SP - 1120 EP - 1127 ER - TY - GEN A1 - Park, Kwan Kyu A1 - Lee, Hyunjoo J. A1 - Kupnik, Mario A1 - Khuri-Yakub, Butrus T. T1 - Fabrication of capacitive micromachined ultrasonic transducers via local oxidation and direct wafer bonding T2 - Journal of Microelectromechanical Systems Y1 - 2011 U6 - https://doi.org/10.1109/JMEMS.2010.2093567 SN - 1941-0158 VL - 20 IS - 1 SP - 95 EP - 103 ER - TY - GEN A1 - Lee, Hyunjoo J. A1 - Park, Kwan Kyu A1 - Kupnik, Mario A1 - Oralkan, Ömer A1 - Khuri-Yakub, Butrus T. T1 - Chemical vapor detection using a capacitive micromachined ultrasonic transducer T2 - Analytical chemistry Y1 - 2011 U6 - https://doi.org/10.1021/ac201626b SN - 1520-6882 VL - 83 IS - 24 SP - 9314 EP - 9320 ER - TY - CHAP A1 - Lee, Hyunjoo J. A1 - Park, Kwan Kyu A1 - Kupnik, Mario A1 - Oralkan, Ömer A1 - Khuri-Yakub, Butrus T. T1 - Highly sensitive detection of DMMP using a CMUT chemical sensor T2 - 2010 IEEE sensors, Waikoloa, Hawaii, USA, 1 - 4 November 2010, the Ninth IEEE Sensors Conference 2010 Y1 - 2010 SN - 978-1-4244-8168-2 U6 - https://doi.org/10.1109/ICSENS.2010.5690493 SP - 2122 EP - 2126 PB - IEEE CY - Piscataway, NJ ER - TY - CHAP A1 - Park, Kwan Kyu A1 - Kupnik, Mario A1 - Lee, Hyunjoo J. A1 - Oralkan, Ömer A1 - Khuri-Yakub, Butrus T. T1 - Zero-bias resonant sensor with an oxide-nitride layer as charge trap T2 - 2010 IEEE sensors, Waikoloa, Hawaii, USA, 1 - 4 November 2010 Y1 - 2010 SN - 978-1-4244-8168-2 SP - 1024 EP - 1028 PB - IEEE CY - Piscataway, NJ ER - TY - CHAP A1 - Park, Kwan Kyu A1 - Kupnik, Mario A1 - Lee, Hyunjoo J. A1 - Khuri-Yakub, Butrus T. T1 - Modeling CMUT of multi-cell configuration T2 - IEEE Ultrasonics Symposium (IUS), 2010, 11 - 14 Oct. 2010, Town & Country Inn & Convention Center, San Diego Y1 - 2010 SN - 978-1-4577-0381-2 SP - 431 EP - 434 PB - IEEE CY - Piscataway, NJ ER -