Magnetic-field-induced photocurrent in metal-dielectric-semiconductor heterostructures based on cobalt nanoparticles SiO_2(Co)/GaAs

摘要

Magnetic-field influence on photocurrent in heterostructures of silicon dioxide films with cobalt nanoparticles SiO_2(Co) grown on gallium arsenide GaAs substrate has been studied in the avalanche regime at room temperature. High values of magnetic-field-induced photocurrent were found in the vicinity and above the GaAs bandgap of ～1.4 eV. For photon energies E ＞ 1.4 eV the photocurrent significantly increases, while the avalanche process is suppressed by the magnetic field, and the current flowing through the heterostructure decreases. The photocurrent is enhanced in the SiO_2(Co 60 at%)/GaAs het-erostructure at the magnetic field H= 1.65 kOe by factor of about 10 for the photon energy E= 1.5 eV. This phenomenon is explained by a model based on electronic transitions in magnetic fields with the spin-dependent recombination process at deep impurity centers in the SiO_2(Co)/GaAs interface region.