School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
J Am Chem Soc. 2009 Dec 9;131(48):17690-5. doi: 10.1021/ja907585c.
A new single nanowire based nanosensor is demonstrated for illustrating its ultrahigh sensitivity for gas sensing. The device is composed of a single ZnO nanowire mounted on Pt electrodes with one end in Ohmic contact and the other end in Schottky contact. The Schottky contact functions as a "gate" that controls the current flowing through the entire system. By tuning the Schottky barrier height through the responsive variation of the surface chemisorbed gases and the amplification role played by the nanowire to Schottky barrier effect, an ultrahigh sensitivity of 32,000% was achieved using the Schottky contacted device operated in reverse bias mode at 275 degrees C for detection of 400 ppm CO, which is 4 orders of magnitude higher than that obtained using an Ohmic contact device under the same conditions. In addition, the response time and reset time have been shortened by a factor of 7. The methodology and principle illustrated in the paper present a new sensing mechanism that can be readily and extensively applied to other gas sensing systems.
一种新的基于单根纳米线的纳米传感器被展示出来，以说明其在气体传感方面的超高灵敏度。该器件由一根安装在 Pt 电极上的 ZnO 纳米线组成，一端为欧姆接触，另一端为肖特基接触。肖特基接触作为一个“门”，控制着整个系统的电流。通过响应表面化学吸附气体的变化来调节肖特基势垒高度，以及纳米线对肖特基势垒效应的放大作用，在 275°C 下以反向偏置模式工作的肖特基接触器件对 400ppm CO 的检测灵敏度达到了 32000%，比在相同条件下使用欧姆接触器件获得的灵敏度高出 4 个数量级。此外，响应时间和恢复时间缩短了 7 倍。本文中所阐述的方法和原理提供了一种新的传感机制，可以很容易地广泛应用于其他气体传感系统。
