Needs["Graphics`ArgColors`"] ;
a = 0.04; b = 0.003; c = 0.0015; i0 = 0.06;
Plot3D[{Abs[(v (a - v) (v - 1) - w + 
              i0 + (b v  -  c w) I)], 
        ArgColor[(v (a - v) (v - 1) - w + 
              i0 + (b v  -  c w) 
                I)]}, 
{v, -0.5, 1.2}, {w, -0.1, 
        0.3}, ImageSize -> {400, 300}, 
      AxesLabel -> {"v", "w", "|v'+i w'|"}]