Graphene and carbon nanotubes are excellent materials for the fabrication of nanoelectromechanical systems (NEMS). Their large stiffness allows to build high frequency mechanical resonators. Their low density makes them sensitive to minute variations of mass and charge. In addition to having outstanding mechanical properties, these materials owe part of their uniqueness to their simplest feature : they constitute the ultimate size limit for one and two-dimensional (1D and 2D) NEMSs. Recent improvement in the fabrication allows us to obtain high purity samples with low dissipation (Q>4.10E4 at 100mK) and GHz frequencies (11GHz). Our measurements signal also an unprecedented scenario, where mechanical dissipation is determined by non-linear damping. All these steps allowed us to reach the yoctogram resolution (10E-24g) of an adding mass on top of these NEMS and to explore new aspects of surface physic.