The spectrum of ALPGE and PC currents. The light spot is fixed on the position of x=+1 mm. (a) The red empty circles denote the ALPGE current as a function of excitation wavelength. (b) The black empty circles denote the common photoinduced current as a function of excitation wavelength. The external electric field applied on the two circle electrodes is 100 V/cm. (c) The blue empty circles denote the ALPGE current normalized by the common photoinduced current. All of the solid lines are for ease of viewing.