Electrical and optical properties of graphene mono- and multi-layers; towards graphene-based optoelectronics

Graphene, a newly discovered material with unusual electrical and optical properties, has attracted interest for a number of potential applications. One of the most actively pursued applications is using graphene as a transparent conducting electrode for use in solar cells, displays or touch screens. In this work, two studies are pursued in parallel to explore the electrical and optical properties of graphene. Graphene was prepared on copper by the standard chemical vapor deposition (CVD) method [1], the preparation procedure and conditions are described in [2]. The effect of chemical p-type doping on graphene stacks was studied in order to reduce the sheet resistance of graphene. The doping decreases the sheet resistance by a factor of 3, yielding films comprised of eight stacked layers with a sheet resistance of 90 Ω/ at a transmittance of 80% [2]. A theoretical model that accurately describes the stacked graphene film system as a resistor network was also developed [2]. The experimental data shows a linear increase in conductivity with the number of graphene layers, indicating that each layer provides an additional transport channel, in good agreement with the theoretical model (Fig. 1).