The photogalvanic effect (PGE) in an asymmetric undoped system of three GaAs/AlGaAs quantum wells illuminated with white light of various intensities is investigated in magnetic fields up to 75 kOe at temperatures ranging from 4.2 K up to 300 K. A maximum of the spontaneous photogalvanic current J(PGE) as a function of the magnetic field predicted by A. A. Gorbatsevich et al., JETP Lett. 57, 580 (1993), is observed, Analysis of the experimental data shows that the main initial characteristic of the PGE is not the spontaneous current but rather the electromotive force E(PGE) arising in the direction perpendicular to the applied magnetic field. It is determined that this emf is independent of the intensity of the incident light, increases linearly with the size d of the illuminated region, and decreases slowly with temperature: E(max)(PGE)similar to 0.8 V at 300 K and similar to 0.1 V at 4.2 K for d similar to 3 mm. The curve E(PGE)(H) at room temperature is determined with allowance for the strong transverse magnetoresistance of the nanostructure. (C) 1996 American Institute of Physics.
