Department of Chemical and Environmental Engineering and Center for Nanoscale Science and Engineering, University of California-Riverside , Riverside, California 92521, United States.
ACS Appl Mater Interfaces. 2014 Jan 8;6(1):319-26. doi: 10.1021/am404328g. Epub 2013 Dec 18.
A Schottky contact-based hydrogen (H2) gas sensor operable at room temperature was constructed by assembling single-walled carbon nanotubes (SWNTs) on a Si/SiO2 substrate bridged by Pd microelectrodes in a chemiresistive/chemical field effect transistor (chemFET) configuration. The Schottky barrier (SB) is formed by exposing the Pd-SWNT interfacial contacts to H2 gas, the analyte it was designed to detect. Because a Schottky barrier height (SBH) acts as an exponential bottleneck to current flow, the electrical response of the sensor can be particularly sensitive to small changes in SBH, yielding an enhanced response to H2 gas. The sensing mechanism was analyzed by I-V and FET properties before and during H2 exposure. I-Vsd characteristics clearly displayed an equivalent back-to-back Schottky diode configuration and demonstrated the formation of a SB during H2 exposure. The I-Vg characteristics revealed a decrease in the carrier mobility without a change in carrier concentration; thus, it corroborates that modulation of a SB via H2 adsorption at the Pd-SWNT interface is the main sensing mechanism.
一种基于肖特基接触的室温氢气（H2）气体传感器，通过在 Si/SiO2 衬底上组装单壁碳纳米管（SWNTs），并在化学电阻/化学场效应晶体管（chemFET）配置中用 Pd 微电极桥接，构建而成。肖特基势垒（SB）是通过将 Pd-SWNT 界面接触暴露于 H2 气体（即设计用于检测的分析物）形成的。由于肖特基势垒高度（SBH）作为电流流动的指数瓶颈，因此传感器的电响应可以对 SBH 的微小变化特别敏感，从而对 H2 气体产生增强的响应。在 H2 暴露前后，通过 I-V 和 FET 特性分析了传感机制。I-Vsd 特性清楚地显示了等效的背靠背肖特基二极管配置，并证明了在 H2 暴露期间形成了 SB。I-Vg 特性显示载流子迁移率降低而载流子浓度没有变化；因此，这证实了通过在 Pd-SWNT 界面吸附 H2 调制 SB 是主要的传感机制。
