The observation of quantum Hall effect and weak localization for hybrid CQDs/graphene device. (a) The resistance of the PbS quantum dots/graphene device as function of the back gate voltage V_BG, taken at B = 0 T (red circle) and B = 4.8 T (black triangle). The measurements are performed with two probe measurement at low temperature T = 1.9 K and at B = 4.8 T. The formation of quantum Hall states with different filling factors ν can be clearly seen. ν =4, 8, and 12 on the hole side are marked with arrows. (b) The temperature dependence of the conductance at V_BG = −10 V and B = 0 T. The red dashed line is the linear fitting of the data in the semilogarithmic scale.