A Single Eu-Doped In(2)O(3) Nanobelt Device for Selective H(2)S Detection

Eu-doped In(2)O(3) nanobelts (Eu-In(2)O(3) NBs) and pure In(2)O(3) nanobelts (In(2)O(3) NBs) are synthesized by the carbon thermal reduction method. Single nanobelt sensors are fabricated via an ion beam deposition system with a mesh-grid mask. The gas-sensing response properties of the Eu-In(2)O(3) NB device and its undoped counterpart are investigated with several kinds of gases (including H(2)S, CO, NO(2), HCHO, and C(2)H(5)OH) at different concentrations and different temperatures. It is found that the response of the Eu-In(2)O(3) NB device to 100 ppm of H(2)S is the best among these gases and the sensitivity reaches 5.74, which is five times that of pure In(2)O(3) NB at 260 °C. We also found that the former has an excellent sensitive response and great selectivity to H(2)S compared to the latter. Besides, there is a linear relationship between the response and H(2)S concentration when its concentration changes from 5 to 100 ppm and from 100 to 1000 ppm. The response/recovery time is quite short and remains stable with an increase of H(2)S concentration. These results mean that the doping of Eu can improve the gas-sensing performance of In(2)O(3) NB effectually.