Hydrophobic Surface Treatment and Interrupted Atomic Layer Deposition for Highly Resistive Al2O3 Films on Graphene
Hydrophobic Surface Treatment and Interrupted Atomic Layer Deposition for Highly Resistive Al2O3 Films on Graphene
复制标题
DOI：
10.1021/acsami.6b09531
复制
发表时间：
2016-11-02
影响因子：
9.5
通讯作者：
Chun, Seung-Hyun
中科院分区：
文献类型：
--
作者：
Jeon, Jae Ho;Jerng, Sahng-Kyoon;Chun, Seung-Hyun
在石墨烯上沉积薄而均匀的介电膜是电子应用的重要一步。在这里，我们通过结合石墨烯表面的简单化学处理和标准原子层沉积（ALD）的修改来解决这个问题。与试图将疏水石墨烯表面转化为亲水表面的常见方法不同，我们采用了相反的方法，通过应用自组装单层六甲基二氮杂烷（HMDS）来制造不依赖缺陷的、更疏水的表面条件。此外，使用三甲基铝（TMA）和水（H2O）的Al2O3 ALD被中断了几次，并且在中断期间表面暴露在空气中以促进后续的ALD过程。这种组合极大地提高了介质膜的均匀性，并成功地在石墨烯上沉积了10纳米厚的Al2O3，除了褶皱和聚甲基丙烯酸甲酯（PMMA）残留物的位置外，其粗糙度为亚纳米级。电化学阻抗测量表明，采用这种改进的ALD工艺，电荷转移电阻增加了300倍。在介质膜生长后，没有观察到拉曼光谱的变化，表明本文提出的方法对石墨烯的质量没有影响。
The deposition of thin and uniform dielectric film on graphene is an important step for electronic applications. Here, we tackled this problem by combining a simple chemical treatment of graphene surface and a modification of standard atomic layer deposition (ALD). Instead of common approaches trying to convert hydrophobic graphene surface into hydrophilic one, we took the opposite way by applying a self-assembled-monolayer, hexamethyldisilazane (HMDS) to make defect-independent, more hydrophobic surface condition. In addition, Al2O3 ALD using trimethylaluminum (TMA) and water (H2O) was interrupted several times and the surface was air-exposed during the interruption to seed the following ALD processes. This combination greatly improved the uniformity of dielectric film and accomplished a successful deposition of 10 nm-thick Al2O3 on graphene with subnanometer roughness except for the locations of wrinkles and poly(methyl methacrylate) (PMMA) residues. Electrochemical impedance measurements revealed a 300-fold increase in the charge-transfer resistance by employing this modified ALD process. No change in the Raman spectra was observed after the dielectric film growth, demonstrating that the method proposed here is nondetrimental to the graphene quality.