Electrical and Computer Engineering, RMIT University, Melbourne, Australia.
Nanotechnology. 2010 Jul 2;21(26):265502. doi: 10.1088/0957-4484/21/26/265502. Epub 2010 Jun 10.
There has been significant interest in using electronically contacted nanorod or nanotube arrays as gas sensors, whereby an adsorbate modifies either the impedance or the Fermi level of the array, enabling detection. Typically, such arrays demonstrate the I-V curves of a Schottky diode that is formed using a metal-semiconductor junction with rectifying characteristics. We show in this work that nanostructured Schottky diodes have a functionally different response, characteristic of the large electric field induced by the size scale of the array. Specifically, they are characterized by a low reverse breakdown voltage. As a result, the reverse bias current becomes a strong function of the applied voltage. In this work, for the first time, we model this unique feature by describing the enhancement effect of high aspect ratio nanostructures on the I-V characteristics of a Schottky diode. A Pt/ZnO/SiC nanostructured Schottky diode is fabricated to verify the theoretical equations presented. The gas sensing properties of the Schottky diode in reversed bias is investigated and it is shown that the theoretical calculations are in excellent agreement with measurements.
人们对使用电子接触纳米棒或纳米管阵列作为气体传感器非常感兴趣，因为吸附物会改变阵列的阻抗或费米能级，从而实现检测。通常，这种阵列表现出肖特基二极管的 I-V 曲线，该二极管是使用具有整流特性的金属-半导体结形成的。在这项工作中，我们表明，纳米结构肖特基二极管具有功能上不同的响应特性，这是由阵列的尺寸引起的大电场引起的。具体来说，它们的特点是反向击穿电压低。因此，反向偏置电流成为施加电压的强函数。在这项工作中，我们首次通过描述高纵横比纳米结构对肖特基二极管 I-V 特性的增强效应来对这一独特特性进行建模。制造了 Pt/ZnO/SiC 纳米结构肖特基二极管来验证所提出的理论方程。研究了肖特基二极管在反向偏置下的气体传感特性，结果表明理论计算与测量结果非常吻合。
