Design and Simulation of a Palladium-Aluminum Nanostructure-Based Hydrogen Sensor With Improved Figure of Merit

We present Palladium (Pd) and Aluminum (Al) nanostructure-based hydrogen sensor in infrared region. Dip strength, full width half maximum, and figure of merit (FOM) are considered for designing the sensor. We numerically demonstrated Pd and Al combination is the appropriate choice for hydrogen sensing as it provides narrow reflection curve in comparison to the reflection curves of Pd-Au combination. Replacing Au by Al, FOM becomes twice. To further improve the performance of the sensor, we optimize the Pd grating depth using rigorous coupled wave analysis method. Using optimized grating depth, FOM could be increased to about 25%. Duty cycle of the structure has also been optimized. FOM of the sensor with optimized parameters is 0.343, and which is about six times higher than that of previously reported grating-based sensor. This proposed sensor can be used for remote sensing of hydrogen gas.