Dynamical thermodiffusion model of graphene synthesis on polymer films by laser irradiation and application to strain sensors

Abstract

A method of graphene synthesis at a desired position on polymer substrates by laser irradiation has been studied. Polyethylene naphthalate films were used as substrates, on which a thin Ni film was deposited as a catalyst layer. The irradiation of a focused laser made a hole in the Ni film and the graphene was synthesized in the hole by the surface decomposition of the polymer. The laser power dependence of the hole radius was successfully explained by a dynamical model of thermodiffusion. The quality of the laser-synthesized graphene was studied by micro-Raman scattering. Typical ambipolar characteristics of the synthesized graphene were observed in field-effect transistors. We studied the application of the laser-synthesized graphene to strain sensors using the sensitivity of the electric conductance to the strain induced by the bending deformation of substrates.

Challenges for Field-Effect-Transistor-Based Graphene Biosensors

“…Composite materials can be expected to acquire new properties, and their specific surface area can be further increased by three-dimensionalization, similarly to metal-organic frameworks [71]; however, this results in the loss of the inherent two-dimensional structure of graphene and reduced carrier mobility. Furthermore, the formats of sensors range from simple single-layer graphene on a chip to flexible and wearable sensor arrays that take advantage of graphene's flexibility [72][73][74][75].…”

350 °C synthesis of high-quality multilayer graphene on an insulator using Ni-induced layer exchange

“…polyimide: 400 °C), but synthesizing high-quality graphene below that temperature is very challenging because most of the methods for synthesizing graphene on insulators require process temperatures of more than 800 °C. [8][9][10][11][12] With great efforts, lowtemperature (⩽ 400 °C) synthesis of graphene directly on insulators has been achieved using laser irradiation, 13) chemical-vapor deposition, [14][15][16] sputtering, 17) and solid-phase crystallization 18,19) with metal catalysts. However, further investigations are necessary to achieve a high-quality, uniform, and thick MLG applicable to the lithography patterning process.…”