Abstract
Chemical vapor deposited graphene suffers from two problems: transfer from metal catalysts to insulators, and photoresist induced degradation during patterning. Both result in macroscopic and microscopic damages such as holes, tears, doping, and contamination, translated into property and yield dropping. We attempt to solve the problems simultaneously. A nickel thin film is evaporated on SiO2 as a sacrificial catalyst, on which surface graphene is grown. A polymer (PMMA) support is spin-coated on the graphene. During the Ni wet etching process, the etchant can permeate the polymer, making the etching efficient. The PMMA/graphene layer is fixed on the substrate by controlling the surface morphology of Ni film during the graphene growth. After etching, the graphene naturally adheres to the insulating substrate. By using this method, transfer-free, lithography-free and fast growth of graphene realized. The whole experiment has good repeatability and controllability. Compared with graphene transfer between substrates, here, no mechanical manipulation is required, leading to minimal damage. Due to the presence of Ni, the graphene quality is intrinsically better than catalyst-free growth. The Ni thickness and growth temperature are controlled to limit the number of layers of graphene. The technology can be extended to grow other two-dimensional materials with other catalysts.
Highlights
As a truly two-dimensional (2D) material, graphene has received worldwide attention due to its unique combination of many special properties such as high carrier mobility, high transmittance and gapless energy band [1, 2]
It is known that the PMMA/graphene stack is permeable to liquid chemicals [11]
We have demonstrated a technical approach of growing lithography-free patterned chemical vapor deposition (CVD) graphene directly on insulating substrates by etching sacrificial metal catalyst through a PMMA support layer
Summary
As a truly two-dimensional (2D) material, graphene has received worldwide attention due to its unique combination of many special properties such as high carrier mobility, high transmittance and gapless energy band [1, 2]. During the process of reproducing these results [17, 19], we discovered that the repeatability of this method is not high and upon etching of the metals, the graphene beneath the metals tends to crack (see figure S1, available online at stacks.iop.org/NANO/29/ 365301/mmedia) This may be due to carbon atoms needing to pass through the metal layer and the lack of polymer support during the metal etching process. We propose a new and facile method to grow graphene directly on insulating substrates by etching sacrificial metal catalyst through a PMMA support layer. We grow graphene on the surface of Ni sacrificial layer instead of at the metal-substrate interface As a result, this growth process is highly repeatable and controllable. The asdeveloped method can be extended to other common graphene catalysts such as Cu (not limited to Ni)
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call