Physico-Chemical nanomaterials science

Electrochemical bubble transfer of Graphene and optoelectrical characterization
Chang Y.1, Zhang J.1, Chen W.1, Zhu H.1, Babichuk I.S.1,2, Yang J.1
1 Faculty of Intelligent Manufacturing, Wuyi University, 529020, Jiangmen, P.R. China. E-mail: 17865599300@163.com (Chang), ivan@szu.edu.cn
2 V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, 03680, Kyiv, Ukraine.
The first two-dimensional (2D) material that was obtained is Graphene (Gr), which is known for its unprecedented physical, mechanical, and thermal properties that often surpass similar properties of other materials. However, practical utilization still requires additional study.
To development biosensor (field-effect transistor - FET) was used high-quality Gr purchased in the company (6Carbon, Shenzhen, China). The Graphene layer from Cu foil on a SiO2/Si substrate was transferred by the bubble method. Electrochemical bubbling transfer of Gr is a technique with high industrial potential due to its scalability, time and cost-effectiveness, and eco-friendliness. The Gr/Cu was spin-coated with poly-methyl methacrylate at 2000 rpm for 30 s and dried in air for 10 min, then put into the oven and dry for 30 min. 2 M NaOH aqueous solution was used in the electrolyte for constant current and voltage 2.3 V. The platinum wire electrode was 0.5 mm in diameter. The delaminated Gr/PMMA film was transferred to SiO2/Si substrate. The transferred Gr was heated at 150 C for 5 min and then cleaned in acetone for 14 h and was washed in Deionized water.
Fig. 1 (a-b) shows that a complete and clean Gr monolayer film was transferred by electrochemical bubbling. It should be noted that the Gr/PMMA layer was separated from the Cu within seconds, achieving efficient transfer of graphene. The Raman spectrum confirms the high-quality transferred Gr layer. Fig. 1 (c-d) shows that a FET prepared with Gr film have a good electrical signal.

Fig. 1. (a) Optical image of the Gr/SiO2/Si sample surface. (b) Raman spectra of Gr with 532 nm laser excitation. (c) Output I-V characteristic curves within the bias ranging from -30 V to +30 V and (d) the transfer I-V characteristic curve at VDS = 1V. Inset: schematic of the device.