Department of Physics, University of Kalyani, Kalyani 741235, India.
Nanotechnology. 2011 Dec 16;22(50):505703. doi: 10.1088/0957-4484/22/50/505703. Epub 2011 Nov 23.
A multistage field emitter based on graphene-linked ZnO nanowire array is realized by means of spin-coating a graphene dispersion (reduced graphene oxide) over a nanostructured platform followed by plasma modification. Spin-coating leads to interlinking of graphene sheets between the neighboring nanowires whereas plasma etching in the subsequent step generates numerous ultra-sharp graphene edges at the nanowire tips. The inherent tendency of graphene to lay flat over a plane substrate can easily be bypassed through the currently presented nanostructure platform based technique. The turn-on and threshold field significantly downshifted compared to the individual components in the cascade emitter. Through the facile electron transfer from nanowires to graphene due to band bending at the ZnO-graphene interface together with multistage geometrical field enhancement at both the nanowire and graphene edges remain behind this enriched field emission from the composite cold cathode. This strategy will open up a new direction to integrate the functionalities of both the graphene array and several other inorganic nanostructure array for practical electronic devices.
一种基于石墨烯连接 ZnO 纳米线阵列的多级场发射器，是通过在纳米结构平台上旋涂石墨烯分散体（还原氧化石墨烯），然后进行等离子体修饰来实现的。旋涂导致相邻纳米线之间的石墨烯片相互连接，而随后的等离子体刻蚀步骤则在纳米线尖端产生了许多极尖锐的石墨烯边缘。通过目前提出的基于纳米结构平台的技术，很容易克服石墨烯在平面衬底上平躺的固有倾向。与级联发射器中的单个组件相比，开启和阈值电场明显下降。由于 ZnO-石墨烯界面处的能带弯曲以及纳米线和石墨烯边缘的多级几何场增强，电子很容易从纳米线转移到石墨烯，这导致了来自复合冷阴极的丰富场发射。这种策略将为整合石墨烯阵列和其他几种无机纳米结构阵列的功能开辟新的方向，以用于实际的电子设备。
