Highly improved ethanol gas response of n-type α-Fe2O3 bunched nanowires sensor with high-valence donor-doping

Mesoporous n-type hematite bunched nanowires (alpha-Fe2O3 BNWs) and Zn-, In- and Sn-doped alpha-Fe2O3 BNWs were synthesized by nanocasting method, and then the influence of the different-valence metals-doping on the microstructures, components and gas-sensing properties is discussed in detail. All samples present mesoporous-structure and are composed of the uniform alpha-Fe2O3 nanowires. The Zn, Fe, Sn and In-doped concentration decreased with the increasing radius of their hydrated ions. The ethanol gassensing results indicate that the different-valence metals-doping greatly affects the response of alpha-Fe2O3 BNWs sensors to ethanol gas. The sensitivity to 100 ppm ethanol gas increased from 10.046 for Fe1.896Zn0.104O2.948 BNWs sensor up to 45.556 for Fe1.938Sn0.062O3.031 BNWs sensor with the increasing metal valence. The high-valence Sn-doping not only decreases the ground state resistance, but also reduces barrier and work function of alpha-Fe2O3 BNWs, which results in the improved the sensitivity of alpha-Fe2O3 BNWs. (C) 2020 Elsevier B.V. All rights reserved.