(593g) Selective Self-Assembly of Graphene Oxide On Monolayer Patterns Deposited by ALD

Electrically conducting transparent film plays an important role in advanced electro-optical devices. Graphene fulfill the requirements of high conductivity, high transparency, and nano-scale size. The fabrication of well-patterned graphene becomes a potential technique to build up the high performance devices. Most of the advanced lithographic methods have been applied to this approach. For example, E-beam lithography and dip-pan lithography (DPN) have been used to make graphene pattern and traditional optical lithography was used to fabricate graphene pad. Thermochemical nanolithography (TCNL) has the ability to modify substrates chemically and mechanically and fits for broader applications. Highly doped AFM cantilever, which could be heated to 1000C, was used to thermally decompose protecting functional groups and activate the specific area for further reaction. This technique also has potential applications in wide variety of areas such as: data storage, optoelectronics, biomimetic and many other devices. TCNL have several advantages to DPN, including higher writing speed and one time tip engagement. It also has the capability to produce multifunctional patterns using a single tip as where DNP has to switch tips and ink etc. On the other hand, it has been demonstrated that TCNL has better resolution (sub15 nm) than electrochemical AFM patterning (~45 nm) where more material was exposed to the potential applied triggering the chemical reaction. In this work, a direct method for controlled patterning of graphene oxide has been developed. This method combines the skill of immobilization of Self-Assembly Monolayer (SAMs), the AFM thermo writing (TCNL), and the deposition of graphene oxide. For the immobilization of SAMs, the mechanism of monolayer formation will be discussed. For AFM thermo writing, the direct measurement of tip temperature by Raman spectroscopy will be presented. The tip temperature has to be well controlled to decompose the masking materials. Some important factors related to resolution enhancement, such as driving force and scan speed, will also be discussed. The reactivity between graphene oxide and SAMs is also a major concern. The relation between graphene oxide flake size and surface coverage density will be reported. The patterning of graphene oxide by TCNL will also be shown.