Dear Dr. Muhammad Farooq Saleem,

Research Articles showing easiest methods of doping graphene.

I hope the information will help you.

With Best Wishes,

Samir G. Pandya

Many researchers have investigated the doped graphene which is effective to tailor its electronic property and chemical reactivity. This work presents a review of the various graphene doping methods and their device applications. As doping methods, direct synthesis method and post treatment method could be categorized. Because the latter case has been widely investigated and used in various electronic applications, we will focus on the post treatment method. Post treatment method could be further classified into wet and dry doping methods. In the case of wet doping, acid treatment, metal chloride, and organic material coating are the methods used to functionalize graphene by using dip-coating, spin coating, etc. Electron charge transfer achieved from graphene to dopants or from dopants to graphene makes p-type or n-type graphenes, respectively, with sheet resistance reduction effect. In the case of dry doping, it can be further categorized into electrostatic field method, evaporation method, thermal treatment method, plasma treatment method, etc. These doping techniques modify Fermi energy level of graphene and functionalize the property of graphene. Finally, some perspectives and device applications of doped graphene are also briefly discussed.

wrt: Graphene Doping Methods and Device Applications

For more details:

1. https://www.techtimes.com/articles/29082/20150127/doping-graphene-easier-now-new-method.htm .

2. Doping graphene with boron: a review of synthesis methods, physicochemical characterization, and emerging applications

In my opinion, The most easiest method is pyrolysis at high temperature with different nitrogen-containing precursor.

you can see the research article showing easiest methods of nitrogen-doped graphene such as: Arc discharge , CVD , Plasma treatment , Thermal treatment , Pyrolysis , Annealing the freeze-dried graphene oxide foams (GOFs) , Facile solvothermal method and Co-polymerization ((B, N) co-doped Graphene formation).

https://doi.org/10.1016/j.jsamd.2017.05.007

Easiest as fastest would be to chemically doped by dropping Brønsted acid (HCl, HNO3, H2S04...). But the effect will not last long (effect start to disappear after several hours and completely after a few days). AuCl3 or other stable dopants can works for longer time. This is for p-type doping after graphene growth, while atomic substitution doping is during growth (Boron for p-type, nitrogen for n-type), but it can create defects like atomic vacancies or structure defects, making it difficult.

ion bombardment

Controlled thermal temperature can increase the N-content of graphene in an NH3 atmosphere with Ar used for ramp and cooling conditions. I would suggest to try bot with N2 and NH3 and compare the results. More details about the same has been discussed in the article:

Article Tuning the structure of in-situ synthesized few layer graphe...

You can add oxygenated groups over CVD graphene surface using oxygen plasma for a very short process time.

You can also use HNO3 or H2SO4 for doping, but using acids, the stability is low.

Please review the following report:

Bautista-Flores, Claudia, Roberto Ysacc Sato-Berrú, and D. Mendoza. "Doping graphene by chemical treatments using acid and basic substances." Journal of Materials Science and Chemical Engineering 3, no. 10 (2015): 17-21.

If you are growing graphene yourself, then you can prepare doped graphene as well by feeding relevant precursors.

Considering that you have purchased graphene on dielectric substrate, post treatment is only the option. That can be done by several techniques as mentioned by everyone above. But crucial point is how much stable will be the doped element and that definitely making an impact for the desired application. Post treatment also introduced the defect in the graphene matrix and other functional group along with the dopant. Sometimes, additional defect and functional group may be beneficial. Thus, you should be very careful to chose the simplest technique which will take less processing time considering the mentioned points.