Non-Destructive Graphene Doping for Nanoscale Electronics
Graphene has been dubbed a “supermaterial” for good reason. At just one-atom thick, it is one of the strongest known materials today. It is also transparent, flexible and conducts heat and electricity significantly better than copper, amongst other strong characteristics Although hailed as a transformative material for the application in nanoscale electronics, its potential in other applications are yet to be fully realized due to various challenges such as the lack of effective doping method of graphene.
The conventional method of doping the graphene involves bombarding the graphene material with energetic ions (dopants), followed by thermal annealing. This destroys the graphene lattice and produces large amounts of defects, which degrades device performance. What is needed is an effective and non-destructive doping method for graphene so that graphene-based nanoscale electronics can become a commercial reality.
This invention disclose a novel method of effectively doping graphene for wafer-scale production of graphene-based electronics devices. It describes the effective surface transfer hole doping of graphene, with the specific example of surface transfer hole doping of epitaxial graphene (EG) on SiC wafer using thermally evaporated MoO3 thin film, which is a chemically- and air-stable dopant. An effective surface transfer p-type doping of EG thermally grown on 4H-SiC (0001) via the deposition of MoO3 thin film on top has been successfully demonstrated. The large work function difference between EG and metal oxides such as MoO3 facilitates electron transfer from EG to the metal oxide thin film. This leads to hole accumulation in the EG layer with an ultra-high areal hole density of about 1.0 ×1013cm-2. The result is a doped surface coating on graphene disposed on a SiC substrate, which has the potential to improve conductivity in devices.
This approach is able to control the charge carrier type and concentration in graphene for the wafer-scale production of graphene-based nanoscale electronic devices such as p-n junction diode rectifiers, field-effect transistors, and photodetectors in the near-to-middle infrared region.