Preparation and characterization of gallium (oxy)nitride powders: Preliminary investigation as new gas sensor materials

Highly reactive gallium oxynitride powders have been prepared by thermal nitridation under ammonia of a gallium oxide precursor synthesized via a soft chemistry process (citrate method). For the first time, thick film sensors were prepared from the oxynitride powders and subsequently compared to GaN thick film sensors prepared from nitride powders obtained by the conventional nitridation of commercial gallium oxide β-Ga2O3. The former showed large ethanol response in comparison to that of the GaN sensors in the 220–320 °C temperature range. The effects of water vapour and sensitive layer thickness on ethanol sensing were also examined. The sensing behaviour of the two materials and the influences of the two parameters – relative humidity and layer thickness – on the latter appeared to be quite different.