Nano Sensor Design for Hydrogen Detection

摘要

In this work, we present the design parameters and optimization of the nanoscale gap interdigitated electrodes (IDEs) for hydrogen gas sensing. In order to extract important design parameters and understand the sensor performance, numerical analysis has been carried out for calculating the electric potential, electrical field and surface charge distribution on the IDEs. The results show that the strength of the electrical field drops with the increase in distance from IDEs depending on the gap spacing and finger width of the electrodes. Based on the sensing mechanism of our sensor, the current distribution inside the sensing film is calculated showing that the thin sensing film could result in fast response due to the uniform electrical field distribution. Effects of the gap spacing and width on the sensing performance were investigated numerically. The optimized design of IDEs with 50 nm in gap and 1,000 nm in width shows that the change of electrical field in the thickness direction is much reduced for a given 120 nm-thick sensing layer on top of the IDEs. It is expected that this design responds better to hydrogen induced conductivity change on top surface and leads to shorter response time.