Study of vertical graphene growth on silver substrate based on design of experiment

Abstract

Due to the different catalytic activity between individual metallic materials, it is always necessary to find optimal conditions for the growth of vertical graphene for the new substrate. In this case, the silver substrate was used as the catalytic layer. The growth of graphene was accomplished by chemical vapour deposition supported by plasma discharge. To find the optimal parameters, a 69-round design of experiment was used with the following input factors: the temperature (500–800 °C), the pressure (200–1200 mTorr), the total flow (30–100 sccm), the methane content in the mixture and hydrogen pre-treatment. Based on the observation by electron microscope, the samples with vertical graphene were selected, which were further characterized. To determine the quality (D, G and 2D peaks intensity) of graphene and number of layers, Raman microscopy was used. The analysis of crystalline structure of graphene was carried out by means of a transmission electron microscope. The size of the deposit was determined by a combination of electron and ion microscopy. The analysis of the data obtained from the design of experiment identified the key parameters of vertical graphene deposition on the silver substrate. Besides, the impact of the individual parameters on the total thickness of the deposited graphene was evaluated.