Photoacoustic Detection of Ammonia and Hydrogen Using Plasmonic Absorption in Pt Functionalized GaN Microcantilevers

III-Nitride heterostructures have attracted significant research interest in recent years because of their multitude of utilities in microwave communications, power electronics and in sensing various toxic gases and volatile organic compounds. In particular, AlGaN/GaN heterostructure Field Effect Transistors (HFETs), when embedded at the base of a GaN microcantilever, can transduce ultra-low displacements with much higher Gauge Factor (GF) compared to their Si counterparts utilizing their unique piezoelectric properties, which can then be utilized in highly sensitive photoacoustic (PA) detection of analytes. [1] The detection sensitivity can be further enhanced using plasmonic absorption in metal Nanoparticles (NPs) deposited on the cantilevers.[2] In this work, we have investigated plasmonically enabled PA detection of NH
₃
and H
₂
using Pt NP functionalized GaN microcantilevers.