Characteristic of Defect Generated on Graphene Through Pulsed Scanning Probe Lithography
Jhe-Wei Liou1*, Wei-Yen Woon1
1Department of Physics, National Central University, Taoyuan, Taiwan
* Presenter:Jhe-Wei Liou,
  Graphene has attracted attention in recent years because of the low dimensional and high electron mobility characteristics. However, the gap-less feature around the Dirac point sets an obstacle for further application. Defect generation is one way to manipulate the band gap of graphene.

  Scanning probe lithography (SPL) is a well-developed nanometer scale technique to functionalized graphene. In our previously work, we formed graphene oxidation thought negative bias SPL. However, the detail of the oxidation processing with scanning probe lithography is still unclear. To understand this, we set up a pulsed scanning probe lithography system with precise pulse width and pulse treatment position control.

  We can clearly distinguish each pattern made by each pulse thought lateral force and topography microscopy simultaneously. Both of those two measurements conclude that pulsed SPL would generate some hole like defects with mean diameter about 160nm. The suppression of graphene Raman features also confirm that graphene is removed by pulsed SPL process. Folding edges around holes can be observed by AFM. The above observation suggests that pulsed SPL produces ablation like process on graphene. With the impedance control, the current can be limit and the transition from ablation to oxidation can be achieved.

  In summary, pulsed SPL demonstrate a mask-less nanometer scale lithography method on graphene. The regulation of the impedance allows the process of functionalization and removal to be controlled.

Keywords: graphene, Scanning probe lithography, wetting property