Improved Sensitivity with Low Limit of Detection of a Hydrogen Gas Sensor Based on rGO-Loaded Ni-Doped ZnO Nanostructures
Improved Sensitivity with Low Limit of Detection of a Hydrogen Gas Sensor Based on rGO-Loaded Ni-Doped ZnO Nanostructures
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DOI：
10.1021/acsami.7b17877
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发表时间：
2018-04-04
影响因子：
9.5
通讯作者：
Kumar, Mahesh
中科院分区：
文献类型：
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作者：
Bhati, Vijendra Singh;Ranwa, Sapana;Kumar, Mahesh
我们报告了用最佳浓度的还原氧化石墨烯（rGO）装饰的Ni掺杂ZnO传感器的增强的氢气敏感性能。采用射频溅射法制备了Ni掺杂ZnO纳米片，Hummer法合成了rGO，并采用滴铸法对rGO进行了不同浓度（0 ~ 1.5wt%）的修饰。负载rGO的传感器的电流-电压特性受到rGO的负载浓度的高度影响，其中，由于在rGO/ZnO界面处形成各种肖特基异质结，当rGO浓度增加到0.75重量%时，电流传导降低并且传感器电阻增加。由于rGO的最佳负载浓度（0.75wt%），在更多活性位点可用性和各种p-n异质结形成的组合效应下，传感器在中等操作温度（150 ℃）下显示出对于100 ppm氢类似于63.8%的最大感测响应。负载rGO的传感器能够检测最低1 ppm的氢浓度，并显示出高选择性。然而，rGO浓度的进一步增加（1.5wt%）导致氢气的相对响应降低，这归因于电极之间rGO互连的形成。因此，它降低了传感器的总电阻，并使p-n异质结对传感器响应的影响最小化。
We report enhanced hydrogen-gas-sensing performance of a Ni-doped ZnO sensor decorated with the optimum concentration of reduced graphene oxide (rGO). Ni-doped ZnO nanoplates were grown by radio frequency sputtering, rGO was synthesized by Hummer's method and decorated by the drop cast method of various concentration of rGO (0-1.5 wt %). The current-voltage characteristics of the rGO-loaded sensor are highly influenced by the loading concentration of rGO, where current conduction decreases and sensor resistance increases as the rGO concentration is increased up to 0.75 wt % because of the formation of various Schottky heterojunctions at rGO/ZnO interfaces. With the combined effect of more active site availability and formation of various p-n heterojunctions due to the optimum loading concentration of rGO (0.75 wt %), the sensor shows the maximum sensing response of similar to 63.8% for 100 ppm hydrogen at moderate operating temperature (150 degrees C). The rGO-loaded sensors were able to detect a minimum of 1 ppm hydrogen concentration and showed high selectivity. However, a further increase in the rGO concentration (1.5 wt %) leads to the reduction of the relative response of hydrogen gas, ascribed to the formation of interconnections of rGO between electrodes. Therefore, it reduces the total resistance of the sensor and minimizes the effect of p-n heterojunction on sensor response.