Controllable and air-stable graphene n-type doping on phosphosilicate glass for intrinsic graphene

We proposed and investigated a controllable air-stable graphene n-doping method on phosphosilicate glass (PSG) to achieve intrinsic graphene. Through Raman, XPS, and AFM analyses, it was confirmed that the initially p-type doped graphene was recovered to intrinsic graphene through n-type doping phenomenon. The n-doping control was accomplished by adjusting the concentration of the out-diffused P₂O₅ molecules from the PSG layer. In particular, a larger amount of P₂O₅ molecules and a smoother PSG surface were achieved after the higher temperature annealing, consequently yielding a larger doping impact on the graphene layer. Finally, a very small Dirac point shift (1-3 V) was observed after 96 h of air exposure, compared to the degree of shift by the n-doping effect (17-36 V), demonstrating that this n-doping method is fairly stable in air.