Nd:YVO₄laser ablation of graphene films on glass and poly(ethylene terephthalate) substrates

Abstract

In this work, a novel processing technique for patterning of graphene monolayer prepared on various platforms, glass and poly(ethylene terephthalate) (PET) substrates, is suggested and experimented for its validity evaluation. Two process parameters of the Q-switched 1064 µm Nd:YVO 4 laser system, scanning speed and repetition rate, were controlled for investigating the geometric features of the graphene line patterns and obtaining an optimum process conditions in the given laser system. The differences among line patterns acquired by controlled process conditions and substrate materials have been investigated and the underlying physics is contemplated. Multiple tools were utilized for evaluating the results, which included an optical microscopy for dimension check, Raman analysis, and G-and 2D-peak mapping technique. Continuous graphene line patterns have been successfully obtained from the most of the schemed process conditions and it would be revealed that the laser pattering is a plausible technique for patterning the graphene monolayers in fabricating various electronic and optical devices.

Understanding of the Mechanism for Laser Ablation-Assisted Patterning of Graphene/ITO Double Layers: Role of Effective Thermal Energy Transfer

“…Furthermore, we also investigated the ablation threshold values for different layers on the PET substrates: the ITO single layer and both the graphene upper and ITO lower layers of the graphene/ITO double-layer structure on each PET substrate have the values of 1.50, 0.30, and 1.31 J/cm 2 , respectively ( Figure 2 b). Compared to the ablation threshold values with the glass substrate ( Figure 2 a), the lower values for each layer on the PET substrates can be explained as a result of the lower thermal conductivity of PET than glass substrate [ 39 , 40 ].…”

“…As the pulsed energy was decreased from 266.5 to 88.1 μJ, the etched spots, even on the ITO lower layer, were still observed, and no spots were found in the case of 44.6 μJ. The etched spot pattern of the graphene upper layer in Figure 4 a was attributed to the different overlapping rates as a result of the scanning speed [ 22 , 40 , 41 , 42 ]. The overlapping etched spot patterns of the graphene upper layer in Figure 3 a and Figure 4 b could be due to the overlapping of the laser beam.…”

“…The difference in the laser-driven etched spot patterns between the graphene upper and ITO lower layers can be explained as a result of the higher thermal conductivity of graphene than that of the ITO layer [ 43 ]. Therefore, it is possible to examine the larger etched spots on the graphene layer and the higher overlapping as the formation of stripes [ 40 ]. Compared to the ITO single layer, a lower ablation threshold and a larger etched spot were investigated on the ITO lower layer of the graphene/ITO double-layer structure.…”

“…For the same material, for example, the graphene layer with PET shows a higher value with increasing σ compared to that with a glass substrate. This result would be possibly due to the lower thermal conductivity [ 39 , 40 ] as well as the possibility of a less-uniform distribution of the heat developed during the laser-ablation process for the former over the latter. Figure 5 a,b show the expected effective thermal-energy transfer of the laser beam through the ITO single layer and graphene/ITO double-layer structure during the laser-ablation process, respectively.…”

Patterning Graphene Film by Magnetic-assisted UV Ozonation

“…Besides taking direct bottom-up fabrication routes12, various top-down etching solutions are used to cut graphene film into certain patterns345678910111213141516. Electron-beam lithography and photolithography techniques are widely used for their high resolution capability to pattern micro-/nanostructures.…”