Room-temperature ozone sensing capability of IGZO-decorated amorphous Ga2O3 films

In present work, we report a room-temperature ozone sensor using InGaZnO (IGZO) decorated amorphous Ga2O3 (a-Ga2O3) thin films. The gas sensing tests demonstrate that the topmost IGZO modification can significantly promote the sensors’ responsivity. Intriguingly, the sensing capability presents a firstly increasing and then decreasing tendency as the surface morphology of IGZO develops from dispersed particles to a continuous film. Finite difference time domain (FDTD) simulation results prove that IGZO nanoparticles can remarkably increase the surface density of photo-generated electrons, which clearly manifests a strong dependence on IGZO particle size and contributes to the boosted responsiveness. However, once IGZO particles coalesce into a thin film, the ozone sensor’s responsivity starts to decrease even though the number of photo-generated carriers still increases. The smaller specific surface area of IGZO thin film is believed responsible for this phenomenon. The proposed ozone gas sensors own the ...