mama-tube well supported by the HOPG. (a) AFM image in contact mode with brighter areas indicating position of MoS2 nano-onions below the thin nanotube wall. Position of line profile is marked. (b) The corresponding magnified normal-force image with clearly resolved nanoparticles below the surface layer. (c) A typical line profile with marked positions of the measured peak (A) and the valley (B) between two underlying particles and (d) bending deformation as a function of load.