Spatial Correlations of Donor Charges in MBE CdTe

Abstract

We present experimental evidence that at high pressures indium donors in CdTe localize electrons in spatially correlated manner. We have studied Hall mobility, μ H , as a function of electron concentration, n H , at T 77 K.Changes of nH have been achieved by two methods. High pressure freeze-out of electrons onto localized states of In-donors leads to the mobility enhancement with respect to the situation when nH has been modified by means of a subsequent annealing of the sample. As a result, depending on the degree of spatial correlations in the impurity charges arrangement, different values of μH correspond to the same value of nH. The variation of mobility with electron concentration suggests that the localized state of In-donor represents likely negatively charged DX state. (929)