Quantitative studies of long-term stable, top-down fabricated silicon nanowire pH sensors
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We report a simple and effective method to develop long-term stable, top-down fabricated silicon nanowire (SiNW) pH sensors along with systematic studies on the performance of the sensors. In this work, we fabricated the SiNW pH sensors based on top-down fabrication processes. In order to improve the stability of the sensor performance, the sensors were coated with a passivation layer (PECVD-based silicon nitride) for effective electrical insulation and ion-blocking. The stability, pH sensitivity, and repeatability of the sensor response are critically analyzed with regard to the physics of sensing interface between sample liquid and the sensor surface. Also, trade-off between the stability and pH sensitivity of the sensor response is discussed.
This research is supported by the U.S. Department of Energy (DOE, Grant #: DE-AC02-05CH112), a grant (2009K000069) from the Center for Nanoscale Mechatronics & Manufacturing (CNMM), one of the 21st Century Frontier Research Programs, and Basic Science Research Program (Grant #: 2011-0004409), which are supported by Ministry of Education, Science and Technology, Korea. S. Choi thanks for his graduate fellowship from the Samsung Scholarship Foundation.
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