Background and Objectives: Research of terahertz (THz) wave rectification in graphene shows the increase of the rectified current in p-n graphene structures relatively to graphene having only n- or p-type of conductivity. The p-n junctions in graphene may be created by both a chemical or electrical doping of graphene. There were discussed several physical mechanisms for wave rectification in graphene structures, that are the photothermoelectric effect, Drude heating of carriers by THz radiation and nonlinear plasmonic effects.