Oscillatory photoconductivity and photomagnetoresistance in the diluted magnetic semiconductor Cd1-xMnxTe

The photoconductivity in the diluted magnetic semiconductor Cd1-xMnxTe has been measured between 0.34 and 4.25 K and in magnetic fields up to 8 T. Below the band-gap energy the photocurrent spectra are interpreted in terms of exciton dissociation. Above the band gap the photocurrent oscillates as a function of energy, and the oscillation period suggests an interaction of hot carriers with longitudinal-optical phonons. Due to the large exchange interaction in this material, the photocurrent spectra shift to lower energy in the presence of a magnetic field. The experimental data are in satisfactory agreement with published measurements of magnetoabsorption. The magnetic-field dependence of the photoresistance was studied at a constant wavelength and for various temperatures. Observed oscillations as a function of magnetic field are explained in terms of exchange and optical-phonon interactions. © 1989 The American Physical Society.