Amplification of the photocurrent in SiO2(Co)/GaAs heterostructure   induced by magnetic field in the avalanche regime
  Amplification of the photocurrent in heterostructures of silicon dioxide films containing cobalt nanoparticles grown on gallium arsenide SiO2(Co)/GaAs has been observed in magnetic field in the avalanche regime. While the avalanche process is suppressed by the magnetic field and the current decreases, for photon energy E greater than the GaAs bandgap energy the photocurrent significantly increases. The amplification reaches 9.5 for E = 1.50 eV. The effect of the photocurrent amplification is explained by the spin-dependent recombination process at deep impurity centers in GaAs. 
V.V. Pavlov, L.V. Lutsev, P.A. Usachev, A.A. Astretsov, A.I. Stognij,   N.N. Novitskii, and R.V. Pisarev
cond-mat.mes-hall