Preparation of graphene samples for its integration in graphene-based terahertz devices

The possibility of using graphene as a key element to develop low-cost terahertz sources has been considered on the basis of theoretical predictions showing non-linear effects leading to frequency multiplication phenomenon. For the integration of graphene in real devices of such kind, special attention must be paid to the processes of synthesis and transfer to suitable substrates, focusing on the needed properties of the final samples. In this work, all the steps followed towards the preparation of the optimal samples of graphene on polyimide substrates are described in detail with particular emphasis on the electrical properties required for the final application.