Wafer-scale hysteresis-free plasmonic hydrogen sensors based on Pd–Au alloy nanoarrays

Abstract

The prospective market of hydrogen energy has dramatically boosted the demand for accurate and stable detection of ambient hydrogen. In this work, we fabricated wafer-scale plasmonic hydrogen sensors consisting of periodically distributed Pd–Au alloy nanodiscs by holographic lithography and other semiconductor-compatible techniques, thus obtaining reliable and low-cost sensing devices. Light transmittance measurements at specific light wavelength close to the plasmonic absorption peak position are conducted to investigate the hydrogen sensing performance on account that optical signals afford spark-free operation and high tolerance. Upon alloying Pd with appropriate content of Au, the hysteresis between hydrogen absorption and desorption curves is completely suppressed which greatly improves the sensing accuracy throughout the hydrogen pressure range of 102–105 Pa. Moreover, the precisely defined Pd–Au alloy nanodiscs provide satisfactory stability and device-to-device reproducibility. This work demonstrates an attractive route into practical applications of hydrogen detection for the facile fabrication method and satisfactory performance.