石墨烯基超薄透明导电氧化物薄膜结构及光电行为

Graphene, due to its two-dimensional sp2 structure and single atomic layer, have excellent conductivity, transmittance and fracture toughness; transparent conductive oxide (TCO) films show their good properties, such as abrasion resistance, etching and adhesion to substrates as well as transmittance and conductivities. Taking the advantages of these two materials, this project will focus on the study of the window electrode multilayer ultra-thin films, i.e. TCO based on graphene, prepared by RF magnetron sputtering. The effect of the sputtering parameters, especially the methods of biasing substrates, on the integration of the graphene and conductive mechanism of the graphene/TCO films is going to be investigated. Also, the electron scattering mechanisms will be explored. Another aspect in this project to be studied is the determination of the relationship between the crystal boundary, lattice deformation and optical, electrical properties of the recrystallized intrinsic and doped TCO. The toughness and optical, electrical properties of the ultra-thin multilayer films, in the structures of substrate/graphene/TCO and substrate/TCO/graphene/TCO, is going to be examined, and the effect of the interface on the electron mobility discussed. The studies of the window electrode multilayer films, including the preparation techniques, properties of the films and conductive mechanisms, is going to be the theoretical and practical guides for the development of graphene on industrial applications. Also, this stufy will lead the development of ultra-thin TCO films.

石墨烯有着高导电、高透光及超强的断裂韧性；透明导电氧化物（TCO）薄膜除了透明导电性能外，还表现出良好耐磨性、可刻蚀性及与基体的良好结合力。二者优势互补，研制可作为窗口电极材料的石墨烯/TCO超薄薄膜。探讨磁控溅射工艺及后处理工艺对石墨烯叠层完整性、石墨烯/TCO导电性作用的物理机制；研究再结晶超薄TCO薄膜的光电性能与晶界面积、掺杂及氧空位造成的晶格缺陷的关系，明确本征及掺杂TCO薄膜中带电粒子的散射机理，探讨晶界散射对再结晶超薄TCO薄膜带电粒子运动的作用；研究基体/石墨烯/TCO、基体/TCO/石墨烯/TCO两种复合形式下，复合界面对超薄膜的断裂韧性（可挠曲性）、导电性作用。对这种新型窗口电极薄膜材料的工艺、性能及导电机理的研究，将向超薄方向拓展TCO薄膜使用，也将成为石墨烯的工业化应用的理论和实践指导。

石墨烯作为柔性电子器件的导电电极有着广阔的应用前景。防止在器件制造过程中划伤石墨烯，造成其导电性能下降，是迫切需要解决的问题之一。在石墨烯表面镀制一层超薄透明保护层，从而形成石墨烯基超薄透明导电薄膜，是解决问题的可行方案。石墨烯基超薄透明导电氧化物薄膜结构及光电行为研究关键而且必要。 项目重要成果包括：..1）.石墨烯复合超薄透明氧化物薄膜，导致其导电性明显下降。实验以射频磁控溅射法、真空蒸镀法制备了氧化锌/石墨烯复合薄膜。磁控溅射方法中采用了在基体前加前阳极方式，以避免溅射中负氧离子对石墨烯的轰击。结果表明，复合薄膜可见光区透光率可达90%，但方块电阻高达106 Ω/sq，带电粒子数低至1016 cm-3。复合薄膜失去了石墨烯的导电性能。.2）.超薄氮化物/石墨烯复合透明导电薄膜可作为透明导电电极使用。实验采用真空蒸镀法在石墨烯/PET上制备氮化镓及氮化钛薄膜。结果表明氮化镓（钛）/石墨烯/PET复合薄膜的可见光区平均透光率为85%，方块电阻216 Ω/sq，带电粒子数1019 cm-3；与石墨烯方块电阻157 Ω/sq，带电粒子数低至1020 cm-3相比，导电性能没有明显下降。.3）.从价键结构方面研究了氧化物、氮化物与石墨烯复合导致其电学性能下改变机理。XPS、红外谱、拉曼谱等检测分析表明，氧化物/石墨烯界面处存在C-O键，氮化物/石墨烯界面处无C-N键。由此表明，氧化物与石墨烯复合可能导致石墨烯的自由π电子与氧结合，而失去了其导电能力。氮化物与石墨烯复合则不破坏石墨烯的导电性。这一结果表明氮化物/石墨烯复合薄膜适于作为超薄透明导电电极使用，并保护石墨烯表面。.4）.与高温难以蒸发氮化钛相比，氮化镓/石墨烯复合超薄膜的光电性能更优，对石墨烯实现全覆盖，起到保护作用。.5）.柔性PET基体上的超薄氮化镓/石墨烯复合薄膜适用于柔性光电子器件。