Abstract
A theoretical analysis of highβfield electron transport in CdTe has been performed with the Monte Carlo technique for different temperatures and ionized impurity contents. The negative differential mobility is due to the combined effect of the increasing population of the lowβmobility satellite valleys and of the intervalley scattering on the mobility of the electrons in the central valley. Which of the above mechanisms is predominant depends on the particular values of physical parameters which, in the case of CdTe, are not yet well known. Ionized impurity scattering maintains its influence on the electron drift velocity also at very high applied fields, above the threshold value (around 10.5 kV/cm at 77 Β°K). At these fields the electron mean energy is very high. and one would expect the effect of such scattering to be negligible. This feature must not be attributed to an effect of the ionized impurities on very fast electrons but rather to the larger number of electrons that ionized impurity scattering keeps in the more randomized low energy part of the distribution function. The present theoretical results are discussed and compared with recent experimental data.