Effect of Fe doping on the NH3 sensing properties of CuO nanostructures

Herein we report an efficient Fe doped CuO based room temperature sensor for ammonia. The sensors were fabricated by a simple solution casting route whereas, the sensing material was synthesized by a low cost hydrothermal method. Different concentration of Fe doping in CuO (0 at.%, 2 at.%, 4 at.% and 8 at.%) resulted in interesting structural and morphological changes. Higher concentration of doping (8 at.%) revealed the formation of rod-like α-Fe2O3 structures with flakes of CuO decorated over the surface. The presence of this α-Fe2O3, found to positively influence the gas sensing properties of CuO. The incorporation of 2 at.% Fe resulted in enhancement of sensor response by two times whereas, the formation of α-Fe2O3 enhanced the sensor response by 5%. The plausible sensor response is attributed to the formation of p–p isotype hetero junctions between CuO and α-Fe2O3 and resulted the change in hole accumulation layer.