Magnetic field effect on current oscillations observed in p-i-n GaInNAs/GaAs multiple quantum wells structures

摘要

The photoconductivity (PC) of two p-i-n GaInNAs/GaAs multiple quantum well (MQW) mesa structures is investigated. When illuminated with photons at energy greater than the GaAs bandgap, at low temperature a number of oscillations are observed in the current-voltage (I-V) characteristics. We found that the position of these oscillations depend upon on the temperature and the magnetic field. Due to the absence of the oscillations in the dark and in the PC at temperatures above 200 K, we explain them in terms of photogenerated electrons thermally escaping from the quantum wells and carrier accumulation. Magnetic fields up to 11 T were applied parallel to the planes of the QWs. A small voltage shift in the position of the oscillations was observed, proportional to the magnetic field intensity and dependent upon the temperature. Calculation of the Landau level energy separation (16 meV) agrees with the observed experimental data.