Transport Properties of CdTe

Abstract

The drift-velocity characteristic for electrons in CdTe has been measured by the transientcharge technique from 77 to 370 °K and for electric fields up to 70 kV/cm. Over this temperature range a negative differential mobility was found. The measured peak drift velocity increases from 1.25 × ${10}^7$ cm/sec at 370 °C to 2.5 × ${10}^7$ cm/sec at 77 °K and is characteristic of intrinsic material. The threshold field decreases from 16kV/cm at 370 °C to 11 kV/cm at 77 °K. At lower temperatures (${10}^4$ kV/cm) the drift velocity varies from sample to sample increasing with increasing trapping time, and is presumably associated with scattering by ionized centers. An increase of the electron trapping time from 4 nsec at an electric field at 2 kV/cm to 45 nsec at an electric field of 30 kV/cm has also been measured at room temperature.