Juvaid M M, Sarkar Soumya, Gogoi Pranjal Kumar, Ghosh Siddhartha, Annamalai Meenakshi, Lin Yung-Chang, Prakash Saurav, Goswami Sreetosh, Li Changjian, Hooda Sonu, Jani Hariom, Breese Mark B H, Rusydi Andrivo, Pennycook Stephen John, Suenaga Kazu, Rao M S Ramachandra, Venkatesan Thirumalai
Nano Functional Materials Technology Centre, Material Science and Research Centre, Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India.
NUSNNI-NanoCore, National University of Singapore, Singapore 117411.
ACS Nano. 2020 Mar 24;14(3):3290-3298. doi: 10.1021/acsnano.9b08916. Epub 2020 Mar 4.
Reduced graphene oxide (rGO) has attracted significant interest in an array of applications ranging from flexible optoelectronics, energy storage, sensing, and very recently as membranes for water purification. Many of these applications require a reproducible, scalable process for the growth of large-area films of high optical and electronic quality. In this work, we report a one-step scalable method for the growth of reduced-graphene-oxide-like (rGO-like) thin films pulsed laser deposition (PLD) of sp carbon in an oxidizing environment. By deploying an appropriate laser beam scanning technique, we are able to deposit wafer-scale uniform rGO-like thin films with ultrasmooth surfaces (roughness <1 nm). Further, control of the growth environment during the PLD process allows us to tailor its hybrid sp-sp electronic structure. This enables us to control its intrinsic optoelectronic properties and helps us achieve some of the lowest extinction coefficients and refractive index values (0.358 and 1.715, respectively, at 2.236 eV) as compared to chemically grown rGO films. Additionally, the transparency and conductivity metrics of our PLD grown thin films are superior to other p-type rGO films and conducting oxides. Unlike chemical methods, our growth technique is devoid of catalysts and is carried out at lower process temperatures. This would enable the integration of these thin films with a wide range of material heterostructures direct growth.
还原氧化石墨烯（rGO）在一系列应用中引起了极大的关注，这些应用涵盖了从柔性光电子学、能量存储、传感领域，以及最近作为水净化膜等方面。许多此类应用需要一种可重复、可扩展的工艺来生长具有高光学和电子质量的大面积薄膜。在这项工作中，我们报告了一种一步可扩展的方法，用于在氧化环境中通过脉冲激光沉积（PLD）生长类还原氧化石墨烯（rGO-like）薄膜。通过采用适当的激光束扫描技术，我们能够沉积具有超光滑表面（粗糙度<1nm）的晶圆级均匀rGO-like薄膜。此外，在PLD过程中对生长环境的控制使我们能够调整其混合的sp-sp电子结构。这使我们能够控制其本征光电特性，并帮助我们实现与化学生长的rGO薄膜相比一些最低的消光系数和折射率值（在2.236eV时分别为0.358和1.715）。此外，我们通过PLD生长的薄膜的透明度和电导率指标优于其他p型rGO薄膜和导电氧化物。与化学方法不同，我们的生长技术无需催化剂，且在较低的工艺温度下进行。这将使这些薄膜能够与各种材料异质结构直接生长集成。
