Formation of FeVO4/ZnO n-n heterojunction with enhanced sensing properties for ethanol

The n-n heterojunction is formed at the interfaces of FeVO4 and ZnO under hydrothermal conditions to increase the mobility of electrons and to decrease the barrier of oxygen activation. The results from X-ray powder diffraction and X-ray photoelectron spectroscopy analyses confirm the co-existence of the FeVO4 and ZnO phases in the composite. The formation of n-n heterojunction and electron transfer behavior are explored by applying electrochemical techniques and corresponding simulation calculation. The FeVO4/ZnO (Fe:Zn = 1:0.5) sensor shows a high response value of S-g = 42 at 300 degrees C, excellent selectivity, fast response, stable, and superior sensitivity for ethanol detection. The effect of the formed n-n heterojunction on enhancing the gas sensitivity for detecting ethanol is discussed by electron depletion theory. When the gas atmosphere is changed from air to ethanol gas, the depletion layer on the sensor surface is also changed significantly, altering the macroscopic resistance of the material. This work offers a new mechanistic understanding of the role of n-n heterojunction in detecting target gases and paves the way for designing excellent selectivity, fast response, and stable sensors based on n-n heterojunctions.

Automated summary

The n-n heterojunction formed between FeVO4 and ZnO under hydrothermal conditions increases electron mobility and reduces the barrier of oxygen activation. The sensor based on FeVO4/ZnO (Fe:Zn = 1:0.5) shows high response, excellent selectivity, fast response, stability, and superior sensitivity for ethanol detection at 300 degrees C. The enhancement of gas sensitivity for detecting ethanol by the formed n-n heterojunction is discussed, providing insights into designing sensors with excellent performance based on n-n heterojunctions.