Observation of different charge transport regimes and large magnetoresistance in graphene oxide layers
Observation of different charge transport regimes and large magnetoresistance in graphene oxide layers
复制标题
DOI：
10.1016/j.carbon.2015.03.019
复制
发表时间：
2015-08
期刊：
影响因子：
10.9
通讯作者：
A. Vianelli;A. Candini;E. Treossi;V. Palermo;M. Affronte
中科院分区：
文献类型：
--
作者：
A. Vianelli;A. Candini;E. Treossi;V. Palermo;M. Affronte
我们报告了一个系统的研究热还原氧化石墨烯（rGO）层的电荷输运性质，从室温到2 K和在磁场的存在下，高达7 T。最具导电性的rGO片遵循不同的传输机制：在室温下，它们显示出类似Arrhenius的行为。在较低温度下，它们表现出热激活行为，电阻R遵循R = R 0 exp（T0/T）plaw，p = 1/3，符合二维Mott变程跳跃（弗赫）输运机制。低于一个给定的temperatureTc，我们观察到一个交叉从VHR到另一个政权，可能是由于缩短的无序二维系统的特征长度。温度Tc取决于rGO的还原等级。我们的rGO薄膜的磁阻ΔR/R也显示出正负之间的交叉，并且低于液态He温度ΔR/R达到大于100 - 60%的值，对于名义上的非磁性材料来说令人惊讶地高。
We report a systematic study on charge transport properties of thermally reduced graphene oxide (rGO) layers, from room temperature to 2 K and in presence of magnetic fields up to 7 T. The most conductive rGO sheets follow different transport regimes: at room temperature they show an Arrhenius-like behavior. At lower temperature they exhibits a thermally activated behavior with resistanceRfollowing aR=R0exp(T0/T)plaw withp= 1/3, consistently with 2D Mott Variable Range Hopping (VRH) transport mechanism. Below a given temperatureTc, we observe a crossover from VHR to another regime, probably due to a shortening of the characteristic lengths of the disordered 2D system. The temperatureTcdepends on the reduction grade of the rGO. Magnetoresistance ΔR/Rof our rGO films shows as well a crossover between positive and negative and below liquid He temperature ΔR/Rreaches values larger than ∼–60%, surprisingly high for a – nominally – non magnetic material.