Dielectric studies of Zn1-xMnxSe1-yTey epilayers

We report on the dielectric properties of Zn1-xMnxSe1-yTey (0.015 < X < 0.0 48, 0.003 < Y < 0.103) epilayers, investigated by capacitance (C) and dissi pation factor (D) measurements in the temperature range 180-460 K and in th e frequency range 20 Hz-100 kHz. A Debye relaxation behavior of the polariz ation has been observed, with the relaxation time decreasing very quickly w ith increasing temperature. We found that the activation energy decreases w ith increasing Mn concentration and Te concentration. In the capacitance me asurements, this energy increases with decreasing test frequency. The deduc ed activation energy from capacitance is consistent with that of the dissip ation factor. We suggest that carrier hopping among structural defects can be used to interpret our results. The change of the activation energy with Mn and Te concentration is explained in terms of the four-center model, in which if the number of Mn or Te atoms increases in the nearest-neighbor sit es of the defect, it can have four possible cofigurations. The measured def ect behavior reflects the overall average of all energy levels involved in the center, and the result is weighted by the relative concentrations. (C) 2001 Elsevier Science Ltd. All rights reserved.