Intrinsic oscillatory photoconductivity and the band structure of ZnTe and CdTe

Oscillations in the spectral distribution of the intrinsic photoconductive response of ZnTe and CdTe at 4.2 K are reported. Up to eleven oscillations are observed at low electric field, gradually diminishing with rising field. The deviation of the period of oscillations from the LO phonon energy yields an electron effective mass 0.11 m0 for ZnTe and average heavy hole effective mass 0.89 m0 for CdTe. A shift of the collector level of oscillations with the applied field is observed. The photoconductivity spectra in the exciton and band gap regions are investigated on differently grown crystals. An explanation of the results is suggested.