Synthesis and enhanced ethanol sensing properties of α-Fe₂O₃/ZnO heteronanostructures

α-Fe₂O₃/ZnO heteronanostructures were synthesized via a three-step process. XRD, SEM, TEM and EDS analyses indicated that their diameters and lengths were ∼40 nm and 0.35-1.2 μm, respectively, in which the largest thickness of ZnO shells was about 10 nm. The heteronanostructures exhibited a dramatic improvement in ethanol sensing characteristics compared to the pure α-Fe₂O₃ nanorods. Based on the space-charge layer model, such enhanced sensing properties were attributed to small thickness of ZnO shell. Our results demonstrate that One-dimensional (1D) metal oxide heteronanostructures, whose shell thickness is comparable to Debye length, are very promising materials for fabricating gas sensors with good performances.